Bridge Guardrails

[markpierce]

You might want to emulate your favorite railroad.  For instance, in the mid-twentieth century on the Southern Pacific the Chief Engineer decided which bridges and tunnels would have guard rails.  Guard rails were used rail and were lighter (not as high) than the running rails.  The guard rails extended two rail lengths (78 feet, not including the end-point casting) from the bridge/tunnel, and started tapering to a point 24.5 feet from the end-point casting.  (More specifics are contained on SP Common Standard plan no. 1645.)  For modeling purposes, you also might want to "compress" these dimensions. 

Mark

[tomikawaTT]

Your question has two separate sets of answers, one prototype and one model:

Prototype - Did the railroad you are modeling use guard rails on bridges, or on that particular design of bridge?  Some put guard rails on everything.  Others only put guard rails on certain kinds of bridges.  Some didn't use them at all.  You will have to research your specific prototype to determine its practices.

Also, there were several different ways of dealing with the bent-in guard rail ends.  Some railroads bolted them to a bull-nose casting, kind of like the center of a frog casting without the wing rails.  Others just brought them close together without connecting them.  I remember once seeing the ends of the guardrails bent downward and buried in the ballast, but I don't remember where or which railroad.

Finally, bridge guard rails are not like switch guard rails.  They do not leave a narrow flangeway.  Rather, they are spaced about 8" inside the running rails; room enough for an entire wheel to settle down with a rail on each side.  The tapered entry, which should be somewhat away from the ends of the bridge structure, is meant to catch the wheels of cars which are derailed but still coupled and force them to run parallel to the rails they should be riding on.

Model - if installed with prototypical spacing, the guard rails will be as dead as lack of electrical connection can make them.  The only time a metal wheel will touch both the running rail and a guard rail is if there is a derailment - in which case, the electrical bridge between them will be the least of your problems.

Chuck (modeling Central Japan in September, 1964)

[UP N-Scaler]

I am looking for some help in configuring guardrails for bridges and overpasses. I currently have several bridges that use Micro Engineering Bridge Track. This system comes with 3' lengths of code 40 guard rail that is to be cut and installed by the user. Does anyone have a good method for bending and bringing the ends of the guard rail to a point or is it acceptable to just put a short radius bend on each end and not have them merge at the track center line. If you do bring them together at the center line, do the two guard rails need to be insulated from each other to prevent shorts? I run metal wheel sets with a Lenz DCC system. Thanks for the help.