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  1. #1
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    Climbing Turns - A distinction without a difference?

    I recently reread J. Johnsonís superb article on trail switchback design and construction (SBTP: Definition of 'switchback' (and exegesis).). I even appreciate all of his railroad references, coming from a family of railroaders and being a big fan of rail trails. However, I find that I strongly disagree with one of the articles key points, that climbing turns are a distinction without a difference.

    Part of the confusion about the term switchback comes from the fact that the word has three different meanings where trails are concerned. The first meaning is the use of the term switchback, generally in the plural, to give a general explanation of how a trail climbs a slope.


    A trail that climbs a slope via the use of linked traverses

    The second meaning agrees with the articles definition of a switchback, which focuses on the function of a turn in a series of linked traverses.


    Reversal of a traverse by means of a turn

    But there is a third definition of switchback, which focuses on the construction of a specific type of traverse-reversing turn.


    A turn where the grade of the trail as it passes through the fall line is less steep than the grade of the slope being traversed

    It is the fact that these three different levels of switchback definitions are often used interchangeably, or even simultaneously, that makes many of the example switchback definitions in the article so confusing.

    So what is the definition of a climbing turn?


    A turn where the grade of the trail as it passes through the fall line is exactly the same as the grade of the slope being traversed.


    There are two tests I believe that can be used to determine whether a turn is a climbing turn or a switchback.

    1) What degree of construction effort involved in creating the turn?

    a. A climbing turn requires less effort to build than an equivalent length of the benched trail leading into the turn. This is because the climbing turn requires no benching or other construction through the apex of the turn.

    b. A switchback turn requires more effort to build than an equivalent length of benched trail leading into the turn. If there is any construction effort involved in creating a turn (excavation, wall construction, tamping fill) beyond basic corridor and tread clearing, the turn is a switchback.

    2) What is the effect of changes in turn radius on the degree of construction effort?

    a. Dramatic changes in climbing turn radius (5 ft. to 30 ft. to 60 ft.) will have no significant impact on construction effort.

    b. Dramatic changes in switchback turn radius have a huge impact on switchback turn construction effort. This is because the greater the switchback turn radius, the more deeply into the hillside the trail needs to be excavated and/or the more the trail must be supported by retained fill.

    The actual radius of a traverse-reversing turn is irrelevant to whether it is a climbing turn or switchback. The effect of the turn radius on the construction effort is what determines the type of turn. A switchback turn on a steep cross slope could have a radius of 100 ft. but it would require a tunnel and a trestle. A climbing turn could have a radius of 3 ft. and still be a climbing turn.

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    Quote Originally Posted by bweide View Post
    I find that I strongly disagree with one of the articles key points
    Maybe instead of posting here you should send the author an email with your thoughts. He did list an email address.

    Btw, thanks for posting the reference to that article. While it was a bit rambling and disorganized I thought it had a lot of nuggets of quality, well founded, trail building wisdom.

  3. #3
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    Great post! We are in the middle of trying to complete get our heads around this too, some of us after 20+ or trail building. I just don't have time right now to read it all and respond. But I will. Thanks for the well thought out post.
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    IMO, it really doesn't take away the more important parts of J. Johnson's ideas if you want to stick up for there being an actual, definable difference between switchbacks and climbing turns. I think this is a distraction because he isn't using this rejection of terminology to argue for building poor quality turns, quite the opposite.

    The problem, as I see it, is that IMBA defines everything that isn't a rolling crown switchback as a climbing turn, and states these are not suitable for steeper slopes.

    IMBA's Trail Solutions acknowledges the existence of "Insloped Turns" as a third type, but states "Wider (toward 15' radius) turns include a lengthy fall-line section that is less sustainable..." which is typical of a climbing turn. In other words, an Insloped Turn is a climbing turn with berms.

    Your way of differentiating between switchbacks and climbing turns acknowledges that it's possible to build a turn with a reduced slope where the turn aligns with the fall line. IMBA doesn't.

    I don't care how you choose your definitions, the important point is that it isn't always necessary to move tons of rock and dirt to make a good turn (although it might be on steeper slopes). Rolling crown switchbacks are not practical for builders without access to machinery or lots of manpower, but we can still build quality, sustainable turns on slopes using J. Johnson's methods.

    Walt

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    Love this conversation guys. I've built lots of turns that, due to the variety of terrain, fall close to the definition of switchback "A turn where the grade of the trail as it passes through the fall line is less steep than the grade of the slope being traversed ", but I concede they're far from near level as in a railroad switchback and feature little more dirt work than the approaching and leaving trail. Whenever possible we'll scout the hills for spots less than half the slope of the general hillside and spot them for turns.

    Shall we call them small crew switchbacks.
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    Quote Originally Posted by hado_pv View Post
    ...they're far from near level... Whenever possible we'll scout the hills for spots less than half the slope of the general hillside and spot them for turns.
    And that's exactly the point I want to stress.

    My guess is that after some number of failed attempts, most trail builders end up building turns to route trail over hills this way. IMBA is pushing rolling crown switchbacks instead, and calling everything else "climbing turns". It's bad information, because it led me, and maybe other people, to route trail poorly in an attempt to avoid the prohibitive labor costs in building rolling crown switchbacks.

    Ultimately, it's my fault for not researching this more carefully, but I still feel let down by the folks who are supposed to be the authorities in sustainable trail building. You can criticize J. Johnson all you want for his writing style and his pet peeves, but if you take the time to work through it, at least you have a practical means of building trail up and down steep hills.

    Walt

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    I posted my comments on J Johnson's article here because he sometimes posts on this forum and switchbacks seems like a good topic for discussion. I agree with him that there are a lot of bad switchbacks out there and a lot of confusion around properly locating/building switchbacks.

    Once we have established we need to build a switchback turn because a climbing turn won't work, then the question simply becomes how do we build the best switchback for the situation. I believe the Forest Service insists on always building rolling crown switchbacks because they are the best switchbacks for use in steep terrain for trails that will be frequented by loaded pack animals. But not all switchbacks will be built in steep terrain or will be used by loaded pack animals, so not all switchback should be built like rolling crown switchbacks.

    The type of switchback turn to build seems to depend both on the steepness of the terrain and the nature of the trail users. For a hiker-only trail the switchback platform doesn't need to be 10 feet across, so a switchback turn requiring much less effort than a rolling crown switchback may be appropriate. On a downhill-only mountain bike trail, a banked wide radius switchback turn might be build that requires significantly more build effort than a rolling crown switchback.

    One specialized type of switchback turn I have seen used in steep terrain on hiker-only trails is a curving staircase built out of step size rocks. The trail is a one-way exit out of a canyoneering canyon, so it only needs to be wide enough for one hiker at a time. The stairs are built at the same grade as the cross slope but it isn't a climbing turn because of the work effort required to build the turns.

    One of the most critical points about building any traverse-reversing climbing or switchback turns is to try to find the least steep spots on which to locate the turns. If you get insanely lucky, you might be able to build all of your switchback turns on flat ground. The other way to reduce the effort of building switchback turns is to reduce the number of turns that need to be built. This can be done by using very long traverses to minimize the number of switchbacks. You can build a lot of benched singletrack for the effort required to build one switchback turn, so it may be the least effort option to replace the switchbacks with long runs of singletrack.

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    I agree that this is a topic worth hashing out. I know that many times I have sat on the side of a hill puzzling over how to reverse direction on a traverse and having a hard time deciding what option to go with. More times than I would like to admit, what got built was not ideal in my mind.

    I find that I also try to avoid switchbacks simply due to the effort it takes to do one correctly. When I'm talking this kind of thing over with other designers on a project I like to express the cost of a structure in linear feet of tread that could have been constructed using the same effort. In fact, I do that with just about anything "Removing that big stump will cost you 150' in linear tread". That thought process does make people pause and rethink whether or not they want to build that many structures.

    Last spring I designed a switchback on a hiking only trail that required a few steps in a short arc to get to the upper leg. At the time I felt guilty about the steps, but looking back on it now I think it was probably the right decision for the requirements of that trail. Way less effort than building out a turning platform and all that was necessary for that type of user.

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    switchbacks - post-grad trail work

    If I looked at 100 switchbacks, I'd guess that only one or two would have been built correctly. The reason is time and effort. I've seen crews spend a full day constructing a switchback that functions. It just isn't complete. Then they walk away, thinking they have spent way too much time on it.

    We all know you could train a bunch of circus monkeys to cut trails. We all have taken volunteer groups out and made trails that are quite nice. But when you get to a spot where you need a switchback, what often happens? All those people with almost no training or experience, thing they can just cut a turn into the hillside. Then they get real tired, real fast, and they start looking for an exit strategy.

    Here is what I teach crew leaders. When you stand at the beginning of the turn on a switchback, and I stand at the point where the turn ends, we need to be eyeball to eyeball. Zero elevation change on that turn. That's right. Half of all switchbacks, and maybe 99% of switchbacks built in wilderness, are simply corkscrews, with utterly unsustainable turns, due to sloppy construction. More accurately, they didn't want to take the time to remove material, or build a retaining wall. Hike down into the Grand Canyon if you want to see some large platformed switchbacks with ten foot high retaining walls. Bike trails won't need that, but you better be prepared to spend a few days on a single switchback, if you want it to work properly and last for years and years.

    I supervised two trail reroutes. Each was about a quarter mile long. One required two switchbacks and the other required only one. The first reroute took five weeks to complete. The second took only five days. Some pictures might help explain why...



























    ...just seeing if you're paying attention. I'll post again to show the first reroute, which was the five week reroute. You'll see why.

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    Switchbacks. Really difficult switchbacks

    So at this end of the canyon, we were working in very rocky conditions. There was a huge thick stone wall that ran along the canyon for a mile. It had this one spot where the wall had collapsed, making an opening for us to route the new trail. We had to build two switchbacks just prior to dropping through that opening in the wall. They both required a lot of work with a pionjar and sledge hammers, along with days of dragging and shaping large boulders to construct the retaining walls. Both switchbacks turned out almost entirely flat, as hoped for. You probably noticed that in the first set of pictures, the turn was not completely flat and the backslope was not properly cut back. We ran out of time and money and took only five days to do build the trail in the first set of pics. I don't consider that switchback to be ideal. The following are a bit closer to the standard...









































    cont.

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    Switchbacks continued...









































    Oops. That last one is part of a whole 'nother story

  12. #12
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    Wow great hard work I'm sure It all paid off

  13. #13
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    wow thanks for all those pics. very helpful.

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    Great pics. Thanks.

    Now, tell us about the fire!
    Apathy will get you exactly what you deserve

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    I wish we could use napalm on our builds too.

  16. #16
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    Quote Originally Posted by The Prodigal Son View Post
    If I looked at 100 switchbacks, I'd guess that only one or two would have been built correctly. The reason is time and effort. I've seen crews spend a full day constructing a switchback that functions. It just isn't complete. Then they walk away, thinking they have spent way too much time on it.

    We all know you could train a bunch of circus monkeys to cut trails. We all have taken volunteer groups out and made trails that are quite nice. But when you get to a spot where you need a switchback, what often happens? All those people with almost no training or experience, thing they can just cut a turn into the hillside. Then they get real tired, real fast, and they start looking for an exit strategy.

    Here is what I teach crew leaders. When you stand at the beginning of the turn on a switchback, and I stand at the point where the turn ends, we need to be eyeball to eyeball. Zero elevation change on that turn. That's right. Half of all switchbacks, and maybe 99% of switchbacks built in wilderness, are simply corkscrews, with utterly unsustainable turns, due to sloppy construction. More accurately, they didn't want to take the time to remove material, or build a retaining wall. Hike down into the Grand Canyon if you want to see some large platformed switchbacks with ten foot high retaining walls. Bike trails won't need that, but you better be prepared to spend a few days on a single switchback, if you want it to work properly and last for years and years.

    I supervised two trail reroutes. Each was about a quarter mile long. One required two switchbacks and the other required only one. The first reroute took five weeks to complete. The second took only five days. Some pictures might help explain why...

    ...just seeing if you're paying attention. I'll post again to show the first reroute, which was the five week reroute. You'll see why.
    The Prodigal Son,

    I'm wondering what I can use from your beautiful examples of well built turns. For instance, you state that "Bike trails don't need that..." in reference to the large, platformed turns in the Grand Canyon. In your opinion, what is acceptable for a switchback for a bike-only trail? Can they be built well with less than a completely flat turn? Is a flat platform necessary? If not, how much grade change can be built in before the turn is "simply corkscrew(s)"

    When you say that you train your crew leaders to build the turn flat from beginning to end, are you referring to the entire ~180 degrees of the turn, or something less? Are the trails you show for use by horses? Again, is something less labor intensive suitable for a trail that is for bike or human feet only?

    It appears that you are working with a crew that is at least part professional (or there are more people working than I'm used to seeing), with some kind of operating budget. If you accept that I'm working in an area with little or no funding for trails, and with very limited volunteer time available, am I out of line to suggest that building to the specs you insist on isn't practical? If so, what do you suggest to aim for?

    Walt

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    Quote Originally Posted by Walt Dizzy View Post
    The Prodigal Son,

    I'm wondering what I can use from your beautiful examples of well built turns. For instance, you state that "Bike trails don't need that..." in reference to the large, platformed turns in the Grand Canyon. In your opinion, what is acceptable for a switchback for a bike-only trail? Can they be built well with less than a completely flat turn? Is a flat platform necessary? If not, how much grade change can be built in before the turn is "simply corkscrew(s)"

    Wow! A bike only trail. How great is that. I have so rarely seen one.

    I like a platform where a tall rider on a large or XL framed bike, can round the turn of a switchback with having to drag a foot on the ground because he is afraid of drifting off a steep drop as he completes the turn. Obviously, an expert level rider can make a much tighter turn than a novice. The key is to use the teardrop shape, not a hairpin shape. Think of those overhead camera shots during the Tour De France, when the Peleton is rind through a series of mountain switchbacks. As the begin entering the turn, the road swings out and the turn is less tight, as a result. Sometimes, you can even have some backslope that is almost like a banked turn on a NASCAR track, that allows bikers to widen the turn by creeping up on the ramped edge as they first enter the turn. This is more easily designed into a bike only trail. I rode a trail in Bend that felt like more than 180 degrees of turn, and all of it steeply banked, to allow riders to keep a lot of speed while making the turn.

    As far as how much less than a flat platform will work, it depends on what part of the country you are building in. Rain and water run-off do not need much slope to create erosion. A totally flat platform could survive years of heavy rains. Even when pack animals trample them. If you have some elevation loss during the 180 degree turn, and on top of that, you have too tight of radius, you'll see riders trying to skid their rear wheel around the turn, intentionally, in hopes of making the turn without stopping or having to put a foot down. Skidding riders on a less than flat platform will create deep ruts in no time. That leads to lose material and rocks of all sizes gathering in those ruts.


    When you say that you train your crew leaders to build the turn flat from beginning to end, are you referring to the entire ~180 degrees of the turn, or something less? Are the trails you show for use by horses? Again, is something less labor intensive suitable for a trail that is for bike or human feet only?

    Yes, the entire 180 degrees is my goal. Yes, these trail get a lot of horse and mule traffic. It tears them up, especially during our monsoon season. I think you can easily build a turn that isn't flat, if it is plenty wide. Plus, just before you begin building the switchback, be sure to create a grade reversal, to run any water off the trail prior to the turn. But if you can put in the time, and the backside of the turn isn't too rocky, keep digging. Think of the turn like a haircut. Stop when you think you've shaved enough off the backside. Ride it a few times. If you got too close to rolling off the edge and had to step out of your pedals, go remove some more material, and widen that turn. I once got suckered into rebuilding ten switchbacks all by myself outside Kingman, Arizona. All of them were lousy. I was totally exhausted. Spent a week digging and digging, trying to flatten and widen those turns. They didn't all end up perfect, but I bet they are still holding up ten years later.

    It appears that you are working with a crew that is at least part professional (or there are more people working than I'm used to seeing), with some kind of operating budget. If you accept that I'm working in an area with little or no funding for trails, and with very limited volunteer time available, am I out of line to suggest that building to the specs you insist on isn't practical? If so, what do you suggest to aim for?

    I've worked for two different conservaton corps and one year I supervised a Forest Service Trail Crew, along with lots of volunteer trail work. The pictures are of a trail project I dreamed up after I flatted on one end of this canyon. I sat and wondered if I could reroute the trail and make it more bike friendly. I talked to a friend at the National Park Service and made a suggestion. He liked the idea and offered our corps $24,000, with the understanding that we had to route the trail off the Parks land. We then needed to contact the Forest Service and State Trust Lands, to get their blessing. I saw we might run out of money and time, so I recruited about 40 Americorps volunteers to spend a day roughing in the trail at one end. I got a few other volunteers to contribute some additional time, and we got it done.

    With little or no funding for trails, you are not out of line suggesting you need to build to different specs. I mentioned one end of this trail reroute was done in five days, while the more challenging end, with all the massive rock retaining walls took five weeks. My boss loves big stone retaining walls. He is great at building them. He wanted me to build several retaining walls at the one end, but I chose to ignore him, and ignore the advice of several experienced trail builders who also wanted retaining walls. It is my belief that end of the trail will last for 100 years. But I suppose the other end, with those rock walls, will be there in 1000 years. So why over, engineer a switchback turn, especially if you lack the funding. Try to recruit some riding buddies to help you out. Maybe buy them lunch. Make it fun. Some of us love building trails for free on our days off. Get you tread done and chip away at the switchbacks. Get the trail opened and listen to feedback. If you feel you need to, return to the switchbacks and cut out more material, until you feel good riding the turn.

    Walt
    Good luck, Walt

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    Quote Originally Posted by bankerboy View Post
    Great pics. Thanks.

    Now, tell us about the fire!
    OK, here is the fire story. About noon on a Sunday afternoon, two years ago, an unattended campfire turns quickly into a wildfire, on a particularly windy day here in Flagstaff.





















    Continued...

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    the rest of the story...

    I rode my bike over to a safe spot and sat there taking pictures. Early the next morning, I got back on my bike and headed out to take more pictures of the tankers that were circling the fire, dropping fire retardent. Only, along the way, I was met with a huge dozer that was pushing down trees and covering the trail I was riding on. I asked him what he was doing, as the fire was miles to the north and moving north. He said he just arrived from New Mexico and was merely doing what he was told to do. I turned around and got on another trail leading up to the top of the mountain, so I could get a better view of the distant fire.

















    This is where the story takes a turn. I made it to the top of the mountain. All I needed to do was ride downhill, on the north side of the mountain, and find a good lookout spot to take some pictures of the fire off in the distance. I head down the trail. All is normal. I could hear helicopters and also some tanker planes were flying overhead. I never thought about why they seemed to be closer than the day before. What I was about to discover was that a portion of the fire had backed up the north side of Mount Elden, despite the winds blowing most of the fire the opposite direcion. So, as I rode down the trail, I began smeling smoke. Then the smoke got dense. Then I stopped my bike and looked uphill to see trees catching on fire. I could feel the intense heat as the fire quickly spread and moved down the drainage I was in. I snapped several pictures and rode back nuphill to escape the oncoming flames.













    Wild ride. Now I'm riding across a ridge, on top of the mountain, heading to another trail that will take me downhill, and away from the fire. I see tankers overhead. I don't want them to drop retardent on me. Helicopters are filling up at a nearby water tank and dropping loads of water on the fire. I safely move away, and can view some of the fires devastation from the day before.

    At this point of the day, the Forest Service had decided to close the forest. They send out crews to place barricades at trail heads and string caution tape across the trail. There are signs advising people the trails are closed, the forest is closed down. I ride downhill and get to a forest road. There are now barricades and caution tape there. I take my last pictures and ride home. I post the pictures on MTBR / Arizona.







    And that's my fire story. Oh wait, there's a bit more. The best part, really. A few days pass. The fire crews get control of the 14,000 acre fire. Only a couple bike trails are damaged. After a week, the FS opens most of the trails again. I head out on a ride the day they open. I get a call, while riding, from a Forest Service LEO. He wants to speak to me. I met him mid-ride, on a forest road next to the single track trail I'm riding. Two uniformed men step out of their vehicle and tell me they are there to arrest me for violating the forest closure. They show me downloaded copies of all the pictures I took. They tell me a mountain biker from MTBR had contacted the FS to tell them I had been in the woods during the closure. They (good friends who I haver been doing trail work for, for over ten years) decided not to call me and ask what my story was. Instead they sent the law dogs out to arrest me. I thought seriously about letting them do exactly that, because I knew I had not broken the law. I had been on a ride when the forest was open. I saw others out on rides, plus some hikers. Then, while many of us were in the woods, the FS closed the trails. We still had every right to get out of the woods while they were placing closed signs at trailheads. I felt it might be entertaining to have a court hearing and prove my innocence. Make my friends at the FS say they were wrong, say they are sorry. But I decided to explain my case to the LEO's, while in my biking gear, in the middle of a ride. I suggested they look at the time stamps on the pictures. One of them pulled out his Blackberry and got on MTBR to confirm what I was saying. Then they said they were sorry to bother me and let me go. The next day, I went to the FS and met with my good friends who tried to get me arrested. They refused to tell me who on MTBR snitched me off. I told them they had betrayed the trust we had once had, and I told them I was disappointed in their behavior. That they could easily have called me and discuss their concerns, before sending law enforcement out to arrest me.

    I guess the fire story had a happy ending. The closed trails reopened two days ago, after two years of restoration work by the conservation corps I work for. I'd be riding down that same trail today, if I didn't have to babysit the flooring installers on there way to our home this morning. But very soon, I will get to visit that trail and enjoy the smoke-free views.

  20. #20
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    Nice "friends"... Great work on the trails!
    Current ride(s) 2011 Santa Cruz Blur LT

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    ^ good story, and great pics!

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    The Prodigal Son

    What I think I hear you recommending when building trail switchbacks is that the legs of the switchback come into the turn separated by some distance so the turn has enough radius that bikes can easily negotiate the turn without slowing almost to a stop. We could call these "separated leg switchback turns". Your switchback reminds of some of the railroad switchback turns I have seen where one leg of the turn forms a deep, curving cut into the hillside and the other leg is suspended by a trestle. In your turn it is a shallower cut and a retaining wall with fill behind it, but the same principle.

    http://

    A normal switchback has the legs entering and leaving the switchback adjacent to each other, so the switchback platform is rarely wider that the combined width of the two trail legs. We could call these "adjacent leg switchback turns". Most switchback turns including the FS recommended rolling crown switchbacks would fall into this group.

    So the question is there a way to build switchbacks that require less construction effort but are still quality switchbacks?

    I think the concern of most trailbuilders have is that both a rolling crown switchback with a platform supported by a retaining wall and your cut/retaining wall method of building switchback turns both require a very significant amount of effort/resources. I have seen situations where organizations that were very capable of building heavy construction switchback turns have rationalized building poor quality switchbacks because they didn't want to spend the time doing it right. Or worse, the have convinced themselves that the hillside is not too steep for a climbing turn and have built a crappy switchback and called it a climbing turn.

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    Quote Originally Posted by bweide View Post
    The Prodigal Son

    What I think I hear you recommending when building trail switchbacks is that the legs of the switchback come into the turn separated by some distance so the turn has enough radius that bikes can easily negotiate the turn without slowing almost to a stop. We could call these "separated leg switchback turns". Your switchback reminds of some of the railroad switchback turns I have seen where one leg of the turn forms a deep, curving cut into the hillside and the other leg is suspended by a trestle. In your turn it is a shallower cut and a retaining wall with fill behind it, but the same principle.

    A normal switchback has the legs entering and leaving the switchback adjacent to each other, so the switchback platform is rarely wider that the combined width of the two trail legs. We could call these "adjacent leg switchback turns". Most switchback turns including the FS recommended rolling crown switchbacks would fall into this group.

    So the question is there a way to build switchbacks that require less construction effort but are still quality switchbacks?


    I think the concern of most trailbuilders have is that both a rolling crown switchback with a platform supported by a retaining wall and your cut/retaining wall method of building switchback turns both require a very significant amount of effort/resources. I have seen situations where organizations that were very capable of building heavy construction switchback turns have rationalized building poor quality switchbacks because they didn't want to spend the time doing it right. Or worse, the have convinced themselves that the hillside is not too steep for a climbing turn and have built a crappy switchback and called it a climbing turn.
    It appears that you and I have some shared experience with volunteers and others trying to construct a switchback. It can be tough when you just knocked out a half-mile of beautiful single track in only three hours, and now you're stuck in one spot for the next four hours, trying to level off a turning platform. Plus you hit a lot of large rocks and have to bring in the brute squad to dig them out or bust them apart. It isn't long before people begin suggesting compromise.

    My answer to your question is no, there is not a way to build a quality switchback with less construction effort. The one of mine you posted fell short of what I desired. The uphill side was a flat slab of rock that you cannot see. We tried beating on it for hours, but ended up with a 14" height difference between the top and bottom points of the turn.

    Those switchbacks you refer to as adjacent leg switchback turns, are adjustable. I've done restoration work on trails and switchbacks and I found I could put several crew members to work on the upper side of the turn and have them dig and dig, giving the turn a more teardrop shape, that allows riders to swing out wide and have a much larger radius turn they can more confidently ride around. This is especially important when you have a retaining wall on the downhill side and there is a severe penalty should you slip over that edge of the turn. In questionable situations like that, most riders play it safe and unclip their inside shoe and dab it as they creep around the turn, just to be safe. Others go a bit further and dismount and walk the turn, to eliminate the risk of serious injury.

    Perhaps there is sort of a solution. Scout out a flatter platform to build the turn on, to begin with. Try not to box yourself in by leaving only one site to construct your switchback on. In some cases, I've seen dualing crews, where one is constructing an uphill section, while another crew is working downhill, with both expecting to meet in a spot suitable to build a turn on. Sort of the Golden Spike method of construction. Once in a while, the two trails will end up meeting, but one is ten feet higher up on the hillside. Oops.

    One last suggestion. Over the years, I'll get to know everyone on a ten person trail crew. There is always 2-3 over-achievers who are also quick learners. Then there will be a couple slugs, who waste all of your time trying to encourage them. Then there are those in the middle, who are going to be pulled either towards the over-achievers, or towards the two who just want to give up. It's the job of the person supervising the crew, to get those people in the middle to want to over-achieve, and ignore the slugs. When you know you will be appraoching a section of trail that requires a switchback, make sure you have already prepped your over-achievers, if you are lucky enough to have some. Get them to buy in on several hours of hard work, harder than they have been doing up to that point. If they can stay focused and keep a good pace, a couple others might take on the challenge and help drag all that material off the trail and allow the main diggers to only have to worrry about digging out the turn. not having to worry about dragging heavy material out of their work area. And if you start seeing people sitting around and distracting the hard workers by engaging them in conversations that cause them to stop working, take action immediately, and find a job for the sitters, that is 100 feet further down the trail. They will cause a 50% drop in output in minutes if you let them.

    I once told a young Korean girl (I work with an international conservation corps) that I left a certain tool back in the work van, and sent her to fetch it. This was just to get rid of her for an hour. She had broken down in tears at one point and sat in the middle of the trail making a scene. Then, when I wasn't watching, she left to take a nature break. I thought she just walked over the hillside for some privacy. She hiked all the way back to the nearest toilet, over an hour hike. That's when I sent her right back to where she just came from, telling her to go fetch a tool. I should have sent her back to camp to begin preparing dinner. She could not find a single tool she felt comfortable using. Not even loppers. And remember; There is no crying in trail building!

  24. #24
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    So one of the critical core principles of switchback construction seems to be the two legs of the switchback, whether adjacent or separated, must be level with each other when they enter and exit the turn. This is why the rolling crown switchback works as well as it does, the large, level platform causes the adjacent legs to be the exact same level. A separated leg switchback is more tolerant of a mismatch in leg heights because the legs are widely separated. A 6" mismatch in separated switchback legs would be barely noticeable but a 6" difference in height between adjacent legs would be problematic.

    The level platform doesn't have to be wide enough for a separated leg switchback or even a rolling crown switchback to form a good switchback. It just has to be as wide as the combined total width of the two legs, somewhere from 36" to 48". So a level platform 36" wide on 18" standard singletrack would not be horse or bike friendly but would be a quality switchback from a sustainability standpoint. The level platform also improves sustainability because the upper leg can be drained across the back side of the level platform.

    The worst switchbacks seem to be adjacent leg switchbacks where the legs never end in a platform but instead just butt up against each other. Because the upper leg is still descending when it encounters the low leg, which is still climbing, two legs will only be level with each other at single point at the farthest point of the switchback. The drop off between the two legs at a point 48" from the end point of the switchback on 10% grade singletrack, will be 10".

    There is also a decision that needs to be made for each switchback about whether to dig the level platform deep into the hillside or built it up out away from the hill side using a retaining wall. Digging deeper into the hillside requires less skill and possibly fewer resources than building a large, stable retaining wall out from the hillside.

  25. #25
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    Is there any more problem with users short cutting the switchback if it's completely level?

    Walt

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