does anyone have any advice on building and operating a HO switchback. how long must each end of the siding be for a train. can a prairie enginge pull up a 5 car train on these switchbacks or do you need a shunting engine?
Switchbacks are usually used to gain elevation where there is no room to put in a turning loop and/or to avoid drilling a tunnel. On logging and industrial lines, the grades on switchbacks could exceed 10%. What I suggest doing is tacking down a couple of lengths of flex track on a 1 x 4 and see how much grade it takes before your loco can't pull the 5 cars without slipping. The tail track(s) of the switchback need to be long enough accommodate the length of your train, with maybe a little extra so you don't run off the end. For your 2-6-2, I am going to guess that a grade of about 3% (1" elevation gain in 36") is about the maximum for those 5 cars.
Here are some links.
http://www.google.com/search?hl=en&ned=us&q=model+railroad+switchback&btnmeta%3Dsearch%3Dsearch=Search+the+Web
Rich
On my H0 home layout, I have a switchback on an industrial branch line. The tail of the switch back is just long enough to accommodate a switcher and two forty foot cars. This requires the operator to double or triple his train up and down the hill. At 8% grade and 15" radius turns, he couldn't handle much more anyway. If an operator starts getting bored with this, he gets a road switcher assigned to him. This requires that he come within a couple of scale feet of the bumper before he can throw the switch. By the time he gets good at that, somebody will "accidentally" drop a 50' car on the exchange track for him. Switchbacks can be a lot of fun.
So is John Allens timesaver,
http://www.wymann.info/ShuntingPuzzles/sw-timesaver.html (http://www.wymann.info/ShuntingPuzzles/sw-timesaver.html)