Mark,
Clearly, whatever the guys did originally didn't work, or there wouldn't have been the observed derailments. Our belief of having the vertical curve moved down to the straight section seems to have worked out, since the problem went away.
There may have been other ways to have handled the problem. We could have kept the same concept of starting the vertical curve just after the frog, but been MUCH more conservative in grade change. That appears to be what you prefer.
However.
Our approach worked.
I do not recall the amount of drop for the passing sidings. Nor do I recall how fast the drop happened, either before or after.
It's my belief that grade changes on straight track are safer than on curved track and/or switches. So, at least for mainline passing sidings, I will stay with that concept.
For steadily decreasing qualities of trackage, I likely would revisit this. I would surely be tempted to do some whoop-ti-doo in industrial trackage--it looks pretty neat. And occasional derailments on such trackage are prototypic.
Ed
mthobbies richhotrain 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. Rich Just build up the area under your yard ladder with the same thickness as your roadbed. Then you won't have any grades and the yard track will be at ground level. For example, if you use 1/4" cork roadbed on the mainline, you can put sheets of 1/4" cork under your yard tracks to bring the top of the rails up to the same height as the mainline. Matt
richhotrain 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. Rich
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.
Rich
Just build up the area under your yard ladder with the same thickness as your roadbed. Then you won't have any grades and the yard track will be at ground level.
For example, if you use 1/4" cork roadbed on the mainline, you can put sheets of 1/4" cork under your yard tracks to bring the top of the rails up to the same height as the mainline.
Matt
Alton Junction
7j43k On a layout for a club I used to belong to, the several mainline sidings were built lower than the main. The grade change happened right at the switch. IN it, really. Derailments galore. We went through all those sidings and moved the grade transition from the switch, past the corrective curve, and into the straight part of the siding. It was fun. We broke out the ballast, jacked up the track, and re-applied more ballast. Kinda like the big guys do. Derailments on those siding vanished. These were passing sidings, not yard tracks. There was plenty of track room to do the trick, something not always available in a (model) yard. Nevertheless, it demonstrated that it is better not to have grade transitions in a switch.
On a layout for a club I used to belong to, the several mainline sidings were built lower than the main. The grade change happened right at the switch. IN it, really. Derailments galore.
We went through all those sidings and moved the grade transition from the switch, past the corrective curve, and into the straight part of the siding. It was fun. We broke out the ballast, jacked up the track, and re-applied more ballast. Kinda like the big guys do.
Derailments on those siding vanished.
These were passing sidings, not yard tracks. There was plenty of track room to do the trick, something not always available in a (model) yard.
Nevertheless, it demonstrated that it is better not to have grade transitions in a switch.
richhotrain 7j43k On a layout for a club I used to belong to, the several mainline sidings were built lower than the main. The grade change happened right at the switch. IN it, really. Derailments galore. We went through all those sidings and moved the grade transition from the switch, past the corrective curve, and into the straight part of the siding. It was fun. We broke out the ballast, jacked up the track, and re-applied more ballast. Kinda like the big guys do. Derailments on those siding vanished. These were passing sidings, not yard tracks. There was plenty of track room to do the trick, something not always available in a (model) yard. Nevertheless, it demonstrated that it is better not to have grade transitions in a switch. That seems to be the majority opinion here, and it makes good sense to me. Thanks, Ed. Rich
That seems to be the majority opinion here, and it makes good sense to me. Thanks, Ed.
It also makes good sense with Union Pacific. Here's what they said in their book "Engineering Track Maintenance Field Handbook":
"The top-of-rail elevation of main and diverging tracks must be level with each other through the turnout, and, where possible, for 250 feet beyond the signal or fouling point, whichever distance is greater."
This was our approach, though we didn't go for the full 250 feet.