Thanks everyone for your comments and suggestions so far. When I look to the prototype for ideas, I can find plenty of photos of yards which all appear at grade level, but the photos don't show the yard ladder. I will keep on looking for protoype photos of yard ladders.
Rich
Alton Junction
Rich,
My approach in situations such as this is "what would the prototype do"? In 1:1 scale, economics is the gorilla in the room.
Most mainline to yard transitions I have seen have the mainline at a greater height than the surrounding terrain for drainage reasons. Considerable expense is tolerated in keeping traffic moving in this regard. Yards, on the other hand, can be bypassed, if flooded. Due to the amount of earth moving required, and the expense involved, a yard was usually laid at grade. To economically go from the mainline to yard a ramp was necessary and, the ladder or, lead was where it was most logical and economical to place the transition. Many older yards were laid out and constructed before the widespread use of mechanization in earthmoving.
At no point has it been said this way is right and that way is wrong or, it was never done that way. It's just to look at the situation from a prototypic point of view, never forgeting the the specter of economics.
How would the railroad you favor have approached this issue?
A lot of people talk about shimming, but that makes little sense to me. I prefer to match the surface of the cork of the mainline to the surface of the yard. That way there is no "ramp" or shimming needed.
Since my mainline subroadbed is installed on risers, I can simply match the surface where the yard surface begins (be it Homasote or foam) to the surface of the cork that is mounted on the mainline subroadbed. No ramp or shimming required. The surface the track is mounted on is at the same elevation.
Here are some photo's where I've done this:
At the very bottom of this photo (below) you can see where the cork matches the yard surface so the track cosses over with no ramping.
This matching surfaces seems totally intuitive but you must built it in during construction to avoid the need for ramps or shims.
Rio Grande. The Action Road - Focus 1977-1983
I've used shimming shingles for years with excellent results. These are available at lumber yards and big box stores like Lowes etc. The best thing about them is they are cheap, they give a very nice gradual transition, and you can cut them to suit your needs very easily.
Their real function is to shim door and window frames to level them up.
Joe
PS. If you do the transition at the mainline-yard junction, you will only need the transition at each end of the yard. That way the whole yard is at the same grade.
When I built my new layout, I began the descent from mainline to yard by transitioning the yard ladder immediately from ballasted track to grade level. However, this resulted in the first couple of turnouts sloping a bit downward as the ladder approached grade level.
Would it make more sense to keep the entire ladder (a series of six turnouts) ballasted at the same level as the mainline and then begin the transition off of the divergent ends of each turnout onto the yard tracks?
I am curious what others do.