I was wondering if there is some sort of pattern or rule of thumb concerning the distance between sidings on single track main lines. I suppose it would have a lot to do with terrain and industries but what I am interested in is just plain Jane flat country with only meets on the rails.
I am certainly not an expert, but I would speculate that the distance between sidings and their length would be determined by the ammount of traffic on a single main branch, as well as the length of trains operated on that branch. Any professionals have the real reason?
The distance varies with the number of movements per day over the line, the average speed of trains over the line, whether or not passenger or hotshot intermodal trains are operated on the line and of course the geography. Assuming there are 8 trains daily, 4 in each direction with an average speed of 35 mph, sidings long enough to accomodate any length train spaced 100 miles apart would keep traffic fluid. If higher speed trains have to pass slower trains in the same direction as well as opposing trains, sidings would have to be much closer, perhaps 30 miles apart.
Interesting! I have read some articles about some divisions which have “not enough sidings” and noticed the charts showed a siding about every 7 to 11 miles. The terrain was mountainous and I believe that there were about 24 trains a day.
Twenty four trains a day is a very busy main line! The old Erie main line between New York and Chicago, which was double tracked, only had 26 trains per day through Ohio and Indiana. Many lines only see two a day - one in each direction.