I'm building a trestle and think I will add a guard rail, but I'm not sure what the spacing you be from the main rail? And is there a difference from what prototypes used vs. what works best for G scale?
Guardrails were installed on most trestles but not all. There are many pics of real trestles and bridges built without guardrails though the majority have them.
Guardrails in a small proportion of cases were set outside the rails - these can be spaced an arbitrary two flangewidths away in the model since they are barely functional in the prototype sense.
If you intend to follow the most common prototype practice locating the guardrails inside the track rails, a starting point is to note that there are no accepted standards for flange fatness in the wheel profile. And if you run Aristo locos, their wheelsets are almost always under gauge. Your guardrails have to be set to handle these situations. My advice would be to take some rail and spike it at a distance from the track rail the same as the guardrail giving the checkgauge at the frog on whatever switches you found acceptable. Code 250 rail (assuming you are using code 332 track) is a little easier to spike in place. Use one truck with the fattest flanged wheelset you have (perhaps gauged to your narrowest loco wheelset since car wheelsets are easily regauged) to test the spacing to ensure it is not too narrow.
Doug, thank you, I appreciate your experience and knowledge of both prototype and model
Paul, great pics! Very nice trestle and bridge. I do see however, in the second pic. the guardrails look considerably further from the main rails than 2 flange widths? Is there a standard for your club?
Also, how do you bend the rails in? Do you use a vise or some other technique?
I doubt that Paul would ever teach this old dog unless he brings extra diet cokes ... The guardrails on that bridge were installed for appearance only and are just set an arbitrary distance in that allowed for easy spiking. They are made of aluminum rail and are easily bent with a pair of needlenose pliers.
I think I references the two flange widths for guardrails set outside the track rails and for thos inside, use a guardrail spacing at a switchfrog as a guide.
It helps also to use a track gauge. I know that some homemade gauges are often used around the IPP&W but they are designed specifically for code 332 rail with a fairly fat railhead. When I used them to handlay some code 215 track, the rails were spaced too far apart and led to derailments. Nonetheless, once you decide on your own standards, make yourself a gauge or two. They are very helpful for checking all sorts of things from teh checkguage at switch frogs to the troublesome too narrow Aristo locos. And at least two three point gauges are needed should you decide to handlay any track.
In the prototype, guard rails are spaced so that if a car derails, the inside wheel of the derailed car will hit the guard rail before the outside wheel hits the guard timber at the very edge of the trestle. The idea is to keep a derailed car from going over the edge.
...therefore, in an absolute practical sense, the standard should be that the guardrail, relative to the opposite guard timber, is no less than the dimension between the inside of the flange on one wheel to the outside of the tread of the other wheel. Theoretically, if your trestle or bridge deck was wide enough, you'd only need one guard rail spiked down the center of the track. Right?
I used Ozark tieplates for the running rails, then put the guard rails to butt up against them. It's a tad hard to spike the guard rail, but as long as the plate isn't wider than the tie there's usually a place to get a bite. Since part of the trestle is curved, I just put guaard rail on the inside rail of the curve rather than onboth sides of the entire trestle.
To be safe, why don't you put a piece in with a minimum number of spikes and "field test" it with your equipment?
I'm actually planning to do something like this later in the year. I initially planned to glue the guard rails in place, but I've also seen folks install long cedar ties between the lgb ties to mimic bridge ties. It's not totally realistic, but it gives the wide bridge tie appearance and gives you something to spike into for the guard rails.
Whoever you are......too bad you couldn't use your name, so that I could respectfully address you....All you need do when wanting to mount guard rails to plastic ties, is to drill appropriate sized holes and use metal spikes. If you use a pin vice and a drill size small enough, the spike can be forced into the holes with enough tightness to stay.
Bridge ties should be used on bridges and trestles. The only plastic tie strip I know of for bridges was produced by a company that doesn't market them now. So...you are stuck to use wooden ties, and hand lay your rail. Don't be afraid to do it. It isn't that hard, and gives your hard work building that bridge, or trestle, the GREAT finished look you will appreciate for years.
I definitely agree with your ideas, but I've seen the "hybrid" done nicely too.
For my project I'm taking a bit of a shortcut for two reasons. First the trestle is very high so I want to be sure the gauge is perfect, So that is why I wish to retain the AML ties. Secondly, I want the wider ties to allow for railed walkways on the bridge to reduce some of the risk of falling. The GMM walkways would have been great but I think they are only straight. This is on a 20ft dia curve that fishes with a buffered curve in the opposite direction.
On a side note...
I joined this board in 2002 (back before the 2008 upgrade). At the time it was more fashionable to use handles than actual names.
With my sincerest respect,
S-4 (Rockwall Canyon Jeff!)