Frisco-kidIn trying to work a logging branch into my new trackplan, I'm up against the same question I had on the last layout - whether or not to try switchbacks on the incline. On the previous one I opted for a tightly-curving incline with a lone switchback at the very top of the grade. I had a wider swath of benchwork to work with with no trackwork below to design around. IMHO - switchbacks look very cool, but I want to do it right if I choose that option. Anybody have any caveats, warnings or success stories to pass along? Aside from "include long enough tail tracks" I don't know much about the "how-to's" of building them as a means to get some elevation along a shorter run.
Did you enjoy the operation of the lone switchback at the top of the grade? Which is more appealing to you - going back and forth through a set of switchbacks, or watching the train climbing a steep curve?
In most cases, the prototype would have preferred the tight curving incline to a set of switchbacks - in general, cheaper and quicker to operate. Switchbacks, especially multiples, are slow and tedious to operate on the prototype - and to some modelers, too. With multiple switchbacks, you have to repeat the same moves every time going from A to B or B to A. Some find this boring, others don't. My rule of thumb is more than 1 pair of switchbacks in a branch is too many.
As for constructing them, allowing room for the vertical transition curve to the grade before or after you get to the turnout is critical. Don't let the vertical curve get into the turnout area. Even though this vertical curve pumps the final grade higher, it is essential for reliable operations. Tail track length is usually the driver on train length for our models, not the grade percent.
Switchbacks and their grades put a premium on good couplers and tight tolerances on coupler installations. Even with reasonable vertical curve transitions, couplers are likely to over/under-ride if heights are not matched from the beginning. Kadee couplers don't let go under load; some other brands have been known to do so. You don't want to watch your train separate, and half roll off the end of the tail track.
Finally, choose your locomotives for the switchbacks with an eye to very good and very smooth slow speed running, and known sustained pulling capability. Nothing detracts more from traversing nicely scenicked switchbacks than a locomotive that visibly jerks at slow speeds. And it has to have the pulling power to get up the grade with the train at low speeds without stalling or slipping.
When you do it right, switchbacks with grades as high as 6-8% are practical and prototypical for logging.
Fred W
....modeling foggy coastal Oregon, where it's always 1900....
The globe has switchbacks spread far and wide because they made/make the most sense for the conditions. When curves are restrictive and grades too, what does a locating engineer do to ensure trains can travel effectively, efficiently, and safely to bring revenue materials to delivery points? In the hills, it often means switchbacks. Laying a switchback and tail may be cheaper than a viaduct by a half-million dollars in 1908, and that's a chunk of change.
I lived in Peru, SA, for nine years as a youth. There was a switchback just above our house where the Central Railway had to gain a lot of height on a mountain promontory. The line horse-shoed up river from our house a few hundred meters and then went past us on a 2.2% slope. A mile later it went past us again, another 200 feet higher, but going in the opposite direction....because of a switchback at the far end.
I like the idea of switchbacks, but they have to fit, both on the layout and for a reasonable purpose.
I have one on my current layout...access to Seneca Coal.
-Crandell
Looking at two aspects, model and prototype:
Operating a switchback is no big thing. Just stop, throw a switch, back up, throw a switch, pull forward. Not even as much bother as spotting a box car at a freight house. You have to uncouple the box car from the train, then spot it properly, uncouple, re-couple to the train... That's equivalent to a three-tail switchback, four when you pull out of town.
Chuck (Modeling Central Japan in September, 1964 - with switchbacks)
fwright As for constructing them, allowing room for the vertical transition curve to the grade before or after you get to the turnout is critical. Don't let the vertical curve get into the turnout area. Even though this vertical curve pumps the final grade higher, it is essential for reliable operations. Tail track length is usually the driver on train length for our models, not the grade percent. Switchbacks and their grades put a premium on good couplers and tight tolerances on coupler installations. Even with reasonable vertical curve transitions, couplers are likely to over/under-ride if heights are not matched from the beginning. Kadee couplers don't let go under load; some other brands have been known to do so. You don't want to watch your train separate, and half roll off the end of the tail track.
I agree with Fred. In addition ...
Switchbacks take a lot of length because the need for the two tails as well as space between where elevation change takes place. My planned switcbacks for six-foot-long branchline trains require about 20 feet of length.
It was good engineering practice to have slight uphill grades (perhaps 1/4 of the maximum grade) on the switchback tails. This made stopping when going down the switchbacks safer, as well as for trains gaining speed when on the uphill journey. This is a feature you might want to include.
You'll have work cut out for you getting nice vertical curves using the WS stuff. I strongly encourage using "cookie-cut" plywood.
Mark
My personal preference. I don't mind switchbacks, but I won't design them into a layout unless I need them. If there is a better way to gain elevation, I'll use it.
That said, my current layout has a logging branch line with one switchback.
Chip
Building the Rock Ridge Railroad with the slowest construction crew west of the Pecos.
tomikawaTT Prototypes: Japan - the Kiso Forest Railway built branches (mostly on low trestlework rather than earthworks) to wherever the woods crews were cutting.
Prototypes: Japan - the Kiso Forest Railway built branches (mostly on low trestlework rather than earthworks) to wherever the woods crews were cutting.
These switcbacks-on-trestles were to a hydro-electric plant in northeastern California (North Fork of the Feather River), located where the line connected to the Western Pacific main track.
SpaceMouse My personal preference. I don't mind switchbacks, but I won't design them into a layout unless I need them. If there is a better way to gain elevation, I'll use it.
The narrow-gauge tourist line in Felton, CA once had a loop to gain elevation, but when the large wooden trestle burned down, the loop was replaced with a couple of switchbacks as this wouldn't require the more expensive alternative of rebuilding the trestle.
markpierce It was good engineering practice to have slight uphill grades (perhaps 1/4 of the maximum grade) on the switchback tails.
It was good engineering practice to have slight uphill grades (perhaps 1/4 of the maximum grade) on the switchback tails.
Since posting the above, I went back to the the section on switchbacks in Clement C. Williams's The Design of Railroad Location (1917, 1924) He cites an extreme example of switcbacks used on the Crown King extension of the Santa Fe. The 18-mile line rose 2436 feet and had ten switchbacks. The switchback tails were 300 feet long. The tails had a grade of 2.0% while the maximum grade between switches was 3.5%. So, my previous statement seems a bit off.
markpierce markpierce It was good engineering practice to have slight uphill grades (perhaps 1/4 of the maximum grade) on the switchback tails. Since posting the above, I went back to the the section on switchbacks in Clement C. Williams's The Design of Railroad Location (1917, 1924) He cites an extreme example of switcbacks used on the Crown King extension of the Santa Fe. The 18-mile line rose 2436 feet and had ten switchbacks. The switchback tails were 300 feet long. The tails had a grade of 2.0% while the maximum grade between switches was 3.5%. So, my previous statement seems a bit off. Mark
That's the route I mentioned last in my 'examples' post. The present-day road bypasses most of the switchbacks, and has a couple of abrupt deviations where the railroad had bridges and a short tunnel (collapsed, IIRC.) It still has four hairpins. A quick Mapquest search is very revealing - it's mostly desert country, and the old roadbed is still clearly visible even though the tracks have been gone for three quarters of a century.
It would make a great prototype for a route climbing up the stairwell from the basement to the first floor...
Chuck (Modeling Central Japan in September, 1964)
Another thing to mention about mark's mentioning of roaring camp's switchback is the grades. The switchback he mentioned is one of the steepest grades found on a conventional railway (without the aid of rack and rail or a cable or something) with the grade being rated at 18%
Are you sure that the Roaring Camp's max grade is 18%? That sounds high even for a shay... all I could find on the internet was a reference to an 8.5% grade at that railroad. That is still very steep, I have been on the Cass where the max grade - depending on which source you believe - is between 9% to 11%. It is very impressive seeing a shay handle a train on those grades through the switchbacks.
All the tips on the switchbacks have been right on target, with the considerations of vertical easements, tail track length and tail track grade. I enjoy operating a switchback where it is appropriate to the railroad and terrain. I even have one on my 12" gauge railroad:
- James
A few years ago my wife gave me a gift of "Engineer for a day" at Roaring camp. Basically it allowed ne to ride in the cab with the crew of the Narrow Gauge Heisler all day. They would let me apply the brakes in a couple of sections and blow the whistle. It was great fun.
I did come away with a couple of impressions from the experience. One was that running a train carries a big responsibility with around a hundred passengers behind you in the coaches. When we ran that switchback, the loco runs straight into the hill... looks like you are going to crash before the engineer applies the brakes at just the right moment...Hardcore..
The second thing was that the owner of Roaring Camp had the narrow gauge line put in specifically to run a tourist railroad. It is not a true prototype railroad. The crew complained that he had wanted a treacherous line with steep grades and sharp curves to attract tourists (How this was supposed to attract tourists was never fully explained to me). The line was made to these specs. The crew pointed out that the grades and curves were very hard on the equipment and that maintenance costs had made management regret this decision later on down the road. Caveat: I have not independently verified this story....FWIW
BTW: If you decide to be engineer for a day (it is a blast -definitely recommended), make sure you protect your ears when they bleed/test the engine brakes in the yard (very loud and unexpected)
Switchbacks on a model? I had a good friend who had some on his layout...not for me.
Guy
see stuff at: the Willoughby Line Site
Gee, all that and we're back where you started? Well, I trust everyone enjoyed the roundtrip.
It's only a suggestion, but I would recommend you keep your grade at six percent maximum. That's plenty of grade to achieve the visual impression of a steep grade and, if you have half a dozen cars, you will find that its a pull (or push) for your locomotive. The maximum grade at Cass is 9%. I have no idea what you will be using for motive power or equipment but keep in mind that the steeper the grade, the more wear & tear you put on the gear train of the locomotive. IF you will be using a Bachmann shay, It won't last long on steep grades. An 80 ton Shay would only be able to handle 5-6 loaded cars at best.
Switchbacks were only used when the railroad ran out of real estate and still needed to gain elevation. Cass had run-around tracks at a switchbacks to keep the locomotive below the train itself. These would be a part of the tail track.