Passing sidings how long would or should they be? - Model Railroader Magazine

I may get jumped up and down on for this... but...

1. Not even the very rich modellers get to model scale length trains or scale length track/facilities.  We all have to settle for what we can fit in and call it "selective comprssion".  This allows us to run half a dozen cars behind two SD70s and ignore the "error",

2. Passing sidings have always been - in essence - long enough between the fouling points at each end to let "normal" maximum length trains to pass with one train "in the clear" inside the siding.

3. Once a railroad has a bunch of passing sidings they will tend to limit the "normal" maximum length of trains through the Division.  This does also relate to Divisions because they were set out for the "natural" runs of their locos - and later locos then conformed to the Division.  So passing sidings for 100 cars hauled by 2 locos on the flat with a cab on the back could be shorter than passing sidings for the same 100 cars with a helper on the front or back... also, a related issue, where RR could they made longer than needed passing sidings so that trains could keep running, even if only barely moving, through them rather than stop and have to start again.

4. On part of a Dispatchers job was to regulate short and long trains so that short trains went into short passing sidings and long ones into long ones... or long ones could run by short ones tucked out of their way.  This also had to be tied in with the priority of trains

5,  One option could be to put two short trains into a long passing siding.

4. At times of peak traffic RR could run "overlength" trains and pass them by working a "saw-by"... someone else can explain that!  ...with diagrams!

6 An issue about long p[assing sidings was the need to ensure that the switches were lined correctly.  Numbers of sidings had the exit end switches spring loaded so that trains automatically ran into the designated side of the siding/passing place and later pushed the blades of the exit switch out of their way when leaving.  Once they had cleared the switch would be spring driven back to the normal/correct position,

7.  A variation of 6 would be for the switch at one end of a siding to be sprung while the other end, probably at or closer to the "station"/telegraph office, was controlled by a switch stand.  The Dispatcher could then telegraph the operator to line the switch to put a train into the siding or let it run through on the Main.  In the other direction trains would almost always run on the Main... This would occur particularly where all trains in one direction had priority over trains in the opposite direction.

8. The longer the siding the lmore likely it would be for one end to be a sprung switch... this related to both the time taklen to change the switch and the need to keep an eye on it.

9 Having a caboose with its crew did shorten the time it could take to get into a passing siding but it still meant stopping to mess about and waiting for crew to rejoin their train.

10 powered switches solved a lot of issues... so the whole question is very era specific... as most questions are.

11. One thing I have seen from c1890-1910 was the idea of having the Main track run through between a p[assing siding on each side of the track.  The sidings were staggered,  They provided two "standard" length passing places but, by setting the switches and producing a wiggle they could be combined to make one long passing siding.  Somewhere I have photocopies of that from RR Journals.  I've never seen it modelled.

Okay... switch #s

You can use any angle of switch you like... but what you must do is inform your Engineers.

If you want your Engineers to run into the passing siding at line speed you've got to go up to a very high #... something like a 20 or more... by which time you are looking at "moveable heal" crossings that close up the gap where the rails cross at the frog/common crossing.

OR... you can put in a #4 switch and tell your Engineers to practically come to a stand before dragging their train into the siding very carefully.

The same will apply at the exit end.

Post this and then give you some more ideas...