Hello,
I have a perplexing situation. I am using the Woodland scenics risers to a 4% grade. At the 4% grade I have an Atlas warren truss bridge going across. I then added a extension piece from woodland (4") and then began my descend downward. At 3" I have another bridge. Essentially a train is going under and behind the incline (Lookes cool).
The problem I am having is as it makes the descend from the 4" extension to the 4" decline there is a slight hump, and the train picks up speed going back down. I was wondering if there was a way to cure this. Im willing to remove the second bridge if need be, but I dont think its a bridge issue (My guess). The foam underneath is completly level and the bench work is level.
Any thoughts?
You need to create smooth vertical curves to get proper operation. I would suggest sanding down the transition between the 4" riser and the downward grade.
Eitherway, you cant simply go from a horizontal tangent to a downward angle without some sort of easement into it.
donny2001 wrote: Hello, I have a perplexing situation. I am using the Woodland scenics risers to a 4% grade. At the 4% grade I have an Atlas warren truss bridge going across. I then added a extension piece from woodland (4") and then began my descend downward.
I have a perplexing situation. I am using the Woodland scenics risers to a 4% grade. At the 4% grade I have an Atlas warren truss bridge going across. I then added a extension piece from woodland (4") and then began my descend downward.
Yes, I have almost the exact thing on my layout, but I have a level section both in front and behind the Warren truss bridge, and had to sand and use an exacto knife to smooth out the transition from the level elevation to the incline/decline risers.
If you didn't do this....that is, put a level section both before and after your bridge, how do your locos behave when they hit the level bridge deck off the riser?..Must be a heck of a snap onto the deck?...or is the bridge deck not level and is integrated into the gradient? I guess that is what you have done. I have mine completely level as that is what I needed at that spot in the mainline.
Let me get this straight. Your train, which has been climbing a 4% grade, picks up speed when it gets to the top and starts down the other side.
Unless your locomotive control has some kind of speed-detecting feedback circuit and automatic compensation, that is what it should be doing! You have gone from fighting gravity to accepting a gravity assist - so the same power setting will result in greater speed due to the decreased load. In fact, on a lot less than a 4% grade the primary purpose of a model locomotive is to prevent the train from running away downgrade.
There are two possible courses of action:
I, personally, have been doing #2 above since I received my first Lionel 027 train set, 70+ years ago.
Chuck (modeling Central Japan in September, 1964)
4% is really steep. Perhaps the first and last riser should be 2%, which gives a little transition.
Dave
Lackawanna Route of the Phoebe Snow
O.k.... shooting off of this topic: I only made one mistake in my plan. I have one section of 4% grade which is all by itself on the layout. I anticipated it as both an operators challenge, but it is also mostly just there to gain elevation.
Like so many others, it seems, i'm trying to put a bridge right at the top of the grade. I'm just curious what the best way might be to reshape the foam riser into a vertical curve to ease the transition to the level crossing of the bridge.
I'm beginning to think this may actually be a major failing point of the WS foam risers, as there is no component for easing the transition at the top of a grade. Particularly with grades of 3 or 4 %, it is likely not healthy nor realistic to have a sudden angle between two sections of roadbed, especially coming up the grade.
You could probably use a hot wire cutter and just remove a little of the "peak" that way.
Use a 2% riser, cut in half, for a transition at both ends.
Donny,
I did the exact same thing that Otis and Stix were saying. I, too, am using the WS 4% risers and I, too, have a bridge right at the top of the completion of the incline. Mine was different, though, in the sense that the loco would go across the 9" straight section of the bridge, then hang a right onto a 18" radius section as it started down the hill. As soon as it would hit the radius, the front trucks would derail. I took my handy-dandy wire foam cutter, measured back 4" from the end of the riser and 1/8" down from the corner, scribed a line with the Sharpie, then trimmed it. Once I re-installed the track, no problems!
Here's a shot of it, if you can make it out!
Skip
Mill Bay I'm beginning to think this may actually be a major failing point of the WS foam risers, as there is no component for easing the transition at the top of a grade. Particularly with grades of 3 or 4 %, it is likely not healthy nor realistic to have a sudden angle between to sections of roadbed, especially coming up the grade.
I agree. After using 3% grade risers and having the same problem with leading trucks popping off the rails (cresting a hill) or coupler pins catching on ties (going downhill or starting uphill), or mystery de-couplings as cars headed over the "break" in the slope, I eventually removed a couple of inches from the ends of each slope, stuck in some foam insulating board, and used a rasp to make a much more gradual transition. No worries now!
If you didn't want to get that agressive, you could probably just take the rasp to the ends of the risers.
Connecticut Valley Railroad A Branch of the New York, New Haven, and Hartford
"If you think you can do a thing or think you can't do a thing, you're right." -- Henry Ford
I've used the 2% risers on my own Yuba River Sub and have several sections where a long grade levels off for a while. I used a rasp to level out the 'bump' where the grade ends, and it worked fine for me. A little messy with all of those little 'beads' flying around until I got the smooth transition I wanted, but it's a fairly quick cure.
Tom
Tom View my layout photos! http://s299.photobucket.com/albums/mm310/TWhite-014/Rio%20Grande%20Yuba%20River%20Sub One can NEVER have too many Articulateds!
Instead of a rasp (in case you don't have one) you could make a simple sanding block out of a scrap of wood, or anything else semi sturdy. Put some fairly coarse sandpaper on it (about 60 grit) and shape it as you need. Similar to the rasp, it will be somewhat messy. I think the sand paper will work a little slower than the rasp, and therefore will allow you to control the contour a little easier. Plus, the rasps I have are only about an inch wide, so it is a little bit of trouble to smoothly shape the width of the track bed. I always end one end a little lower than the other, so now the track leans from left to right. If you make your sanding block wider than the foam riser, you will gaurantee the road bed will be level as you contour the slope.
I have a 2" wide rasp, which works like a charm. I use that for shaping and 80 grit sandpaper for smoothing.
Although, speaking from experience, even with a wide enough rasp or sanding block, you have to make the distinction between "flat" (as in, in the same plane) and "level".... Superelevation, anyone?
If you use the WS hot wire cutter, there's no mess left over like when sanding or using a rasp. If you want, you can cut templates out of cardboard and use that to guide the cutting wire.
I re-engineered my grades by going back and swapping out the top end of the 4% grade run with 2% risers instead and trying to keep the vertical transitions as shallow as I could. The track seems to be fairly level at it's transition point now and I'll be testing it all soon to see how well it works out.
This foam stuff will never work with handlaid track for me. And half-inch plywood makes great transition curves: one doesn't need to be a sculpture to form grade transitions. Foam roadbed is a piper I'll ever follow unless I had a mind to laying pre-made track on a level, table top layout/module. I believe the current generation has an irrational fear of saws.
Mark