I'm building a stone viaduct and started thinking about the track, and I started to wonder if there would be guard rails. I'm thinking not, but it got me thinking about where I have and have not seen them on bridges; and I have no idea when the railroads used them and when they did not. Anyone know what the rule was on guard rails over bridges?
I can't quote any rule, but I can provide precedent. I'm looking at a steam era photo of the famous PRR Rockville Bridge crossing the Susquehanna River near Harrisburg, PA. It is a 30-plus span stone arch bridge carrying a 4 track main. The photo I'm using is on page 35 of Jim Kelly's Trackside Scenes book from Kalmback Books. The photo shows steel pipe handrails down both sides of the bridge. It appears they are intended to keep crewmembers from taking an unplanned swim while walking along a stopped train. I haven't personally seen any older stone or concrete bridges in service. I've seen some abandoned concrete bridges without rails. However, the absence of handrails long after abandonment doesn't necessarily indicate that handrails did not previously exist while the bridge was in service.
First of you should use bridge track. It can be found on micro engineerings web site. It has longer ties spaced closer together. Also you need another set of smaller rails in the middle which should extend 50-60 scale feet beyond the bridge, were they should bend together. You should also lay wood planking between the outside edge of the ties and the rails all the way across the bridge. Those are called "guard rails" but other than that you need no rails for humans. They arent needed in real life and they look cheesy and ruin pictures. If you look on rail images at n scale and look up BN caboose, you will see a picture of one of my custom cabooses on an open deck bridge with the configuration I just explained. I hope your project turns out well.
That sounds right for a open deck bridge, but what about other sorts of bridges? In my case I'm building a stone arch viaduct, since it's ballasted I don't think the bridge flex is right, it's normal tie spacing, but I don't know about the inner (smaller) guard rails. I wasn't thinking people guard rails, but that's an interesting idea as well.
Leo, I did a quick google search for starrucca viaduct, and came up with this page: Conrail Southern Tier East scroll down and look to the right side. It shows guard rails only on the inside side of each track. -Mike
Here are photo's of the Canton Viaduct built in Canton Massachusetts in 1835. It is 635 feet long. There are only two similar viaducts like it in the world. Both are in Russia. I lived in Canton for over thirty years before moving to Florida in 1994. My Dental office building was about 3/4 mile south of the Viaduct in downtown Canton.
Hello, Leo ! Just an observation, not engineering knowledge - Guard Rails (if I understand what you're referring to) are to keep derailed wheels/trucks from sluing perpendicular to track direction and adversely affecting what is already a bad situation. My experience is; open deck bridges have 'em (in one form or another), ballasted decks don't. Length of the bridge may also be a consideration (by operating corp.), but don't know that as fact. Heck, they look neat and might actually be effective on scale bridges, saving a trip to the concrete. Haven't looked yet, but WIKIPEDIA may have some info/examples you can use. Happy modelling - my fingers are tired !:tb-wacky: Bob C.
In addition they prevent the wheels from tracking toward the edge of the bridge and falling off - pulling several other cars with them. Single-track deck bridges thus tend to have longer ties (to keep the outer derailed wheels on them) and guard rails inside both tracks to keep a derailed wheel close to its rail. Most double-track bridges only have them on the inside rails since that would be a derailment toward the outside of the bridge with a chance of falling off. The other track and its guardrail serve as the guard for a derailment to that side.
Oh, THOSE guard rails! Sorry about briefly sending things off on a tangent. Having dealt with miles of guardrail in the highway construction world, my default definition of that term had to catch up with the topic at hand. I've used the ME bridge track successfully so far for a deck truss shown here. The carrier rails are code 55 and the guard rails are code 40. All my other bridges have ballasted decks and I haven't installed guard rails yet. I used Peco code 55 throughout. Someday, I'll get around to adding guardrails to my other bridges. Thanks for the thread. I've learned something useful here today.
