Guard rails on bridges

[areibel]

I had a friend ask me why there were two sets of rails on some railroad bridges but not on others.  He's referring to the inner set of guard rails laid inside the gauge of the main rails, I had always assumed that they were to prevent any major side to side movement of rolling stock in case of a derailment but I wasn't sure if that's the only reason or not?
Thanks!
Al

[Firelock76]

As far as I know that's the exact reason those extra rails are there.  Some railroads applied them, some didn't.

[tree68]

On double track bridges, sometimes you'll only see one side of the guard rail.  Presumably, the other track will keep things in line.

[tomikawaTT]

The guard rails are intended to keep derailed wheels close to and in line with the running rails,  That's why they're separated from the running rail by somewhat more than the thickness of a wheel.

Some roads install them on every elevated structure.  Others only use them on structures where a derailed car might damage bridge structure above tie height.  Still others just disregard the need - especially if the bridge has a ballasted deck.  To find out which your pet prototype prefers, hunt up a copy of their specifications for right of way and trackwork.

Sometimes guard rails are installed in what would seem odd places:

• Inside a tunnel.  The most extreme example I encountered had continuous guard rails from one tunnel portal (started about forty feet short of the bore) to the far end of a second tunnel.  Both tunnels were long - and they were separated by a concrete arch bridge that spanned a gorge.  [The tunnels and bridge are still there, but they haven't felt the weight of a train for half a century or more.]
• Continuous single guard rail on the field side of an electrified double track main that carries incredible traffic density.  I won't say exactly where, but both Fujisan and a Pacific Ocean beach are visible in the photo.
• Bridge guard rails that look like something swiped from an abandoned mine - 25#/yd (maybe) and spiked every fifth tie.  Not some lightweight branch line, judging by the tripleheaded 2-8-2s crossing the bridge.

Chuck (railfan emeritus)

[jeffhergert]

What was told to me years ago was that guard rails were required on lines that had regular passenger trains.

That being said, there were times when freight only lines would have guard rails on some bridges.  Such as those where a derailment could cause damage to the structure.

Jeff

[NorthWest]

tomikawaTT

nside a tunnel. The most extreme example I encountered had continuous guard rails from one tunnel portal (started about forty feet short of the bore) to the far end of a second tunnel. Both tunnels were long - and they were separated by a concrete arch bridge that spanned a gorge. [The tunnels and bridge are still there, but they haven't felt the weight of a train for half a century or more.]

This sounds quite interesting! I'd like to Google Earth it. Where is it?

[roymathew]

yes we follow your comments..

[tomikawaTT]

NorthWest

 

 

tomikawaTT

Inside a tunnel. The most extreme example I encountered had continuous guard rails from one tunnel portal (started about forty feet short of the bore) to the far end of a second tunnel. Both tunnels were long - and they were separated by a concrete arch bridge that spanned a gorge. [The tunnels and bridge are still there, but they haven't felt the weight of a train for half a century or more.]

 

 

This sounds quite interesting! I'd like to Google Earth it. Where is it?

 

 

The extension of the Ome-sen beyond the city of Okutama, in the wilds of western Tokyo (which is a prefecture and extends well beyond the Tokyo Metroplex.)  The tunnel-bridge-tunnel is actually within the Okutama township, starting not too far from where the EMU platform ends.  There are others farther up the valley.

 

That extension was last used to move materials to the Ogochi Dam.  Before that, IIRC, it served a couple of mines which are now submerged in the lake.

 

Chuck

[NorthWest]

Thanks! Reminds me a lot of Peru's Infiernillo.

[Lake]

While looking google satillite for Okutama, I spotted and jet passenger aircraft heading NW, over the Tama river just south of Sakai. Most likey coming from the Tokyo area.

 

[tomikawaTT]

Lake

While looking google satillite for Okutama, I spotted and jet passenger aircraft heading NW, over the Tama river just south of Sakai. Most likey coming from the Tokyo area.

Most likely coming from Yokota AB, which is located NW of the major rail junction at Haijima.  Yokota was (and probably still is) the major Port of Aerial Embarcation for US Forces Japan.

A full tour at Yokota is the reason I'm rather familiar with the area.

Chuck, MSgt(ret) USAF

 

[Paul_D_North_Jr]

Two Penna. RR Standard Plans for Guard Rails - the notes indicate where they are to be used:

http://prr.railfan.net/standards/standards.cgi?plan=54343-B 

http://prr.railfan.net/standards/standards.cgi?plan=61324-D 

Cast Malleable Iron "Nose for Bridge Guard Rails":

http://prr.railfan.net/standards/standards.cgi?plan=61325-B 

- Paul North.

 

[cefinkjr]

tomikawaTT

Yokota was (and probably still is) the major Port of Aerial Embarcation for US Forces Japan.

Is that where I would have paused for refueling en route to Korea in 1964?  I was among the first to rotate to Korea via air.  Arrived well before the last ship-load of replacements which had left the U.S. before us.  Rewarded by a longer in-country tour.

We flew in a Pan Am 707 from San Francisco via the Aleutians to Japan.  I think we may have been flying on fumes by the time we got to Japan.  My clearest memory of the stop is that we were required to get off the plane and sit in a chilly hanger (after midnight) until the refueling was finished.  Finally arrived Kimpo very early the next morning.