Steam era tunnels and structures and modern double stacks,a natural fit?

Model Railroader Prototype information for the modeler
1

I couldn’t find any picture of a steam locomotive exiting a tunnel so can’t really tell but it’s my impression that steam era tunnels were bored barely high enough to clear the smoke stacks of the bigger locos.Am I right or am I completely off here?I’m curious to know.But then,if such was the case,were tunnels rebored to accomodate modern double deckers and double stacks or the railways simply avoid these lines with these cars.Also,was it the case with bridges and overpass?Were they originally built high enough or were they somehow raised or else,were the tracks lowered?I have models of both eras and it is obvious that my double stacks are pretty much higher than even my Big Boy,wich got me thinking…

2

Tunnels were bored to clear AAR “plates”, standard clearance diagrams.

Cars and engines were designed to clear inside those plates also. So its not so much that the tunnels were designed to clear the engines as the tunnels and engines were designed to be a similar size.

Yes many modern tunnels have had to be rebored (the top raised), lowered (the floor dug down) or other tricks (using steel ties that are 6 inches thinner than wood ties, to gain clearance.

One of the latest efforts is “notching” where a notch is ground out of the upper corners of the tunnel to just clear a tall double stack. Both the UP and NS have recently opened major corridors to double stacks by notching.

3

Some very old tunnels, bored though hard rock with hand drills and black powder, had very tight clearances - and an adverse influence on what could be routed through them. Probably the worst offenders were the old tunnels north of Peeksill, NY, in the Hudson River Narrows, which caused the New York Central to build their steam a foot lower than that used on Western roads and kept dome cars out of Grand Central. (To see what I mean, put models of 844 and a Niagara side by side.)

Can’t remember where I saw it, but I did see an interior view of a tunnel that had been ‘notched’ - two new grooves in the arched concrete tunnel liner, just a couple of inches deep and maybe a foot across.

The Gallitzin tunnels on ex-PRR, (now) ex-Conrail, were dug down for clearance. Apparently, the job ended up with a complete re-bore and re-lining as well. Prior to that, a single track had been laid down the center of what had been built as a double track tunnel in an attempt to get sufficient clearance - it wasn’t enough, and switching taller trains onto the one track that could clear them created scheduling problems.

As for road overpasses, more than a few that had been level now hump up to clear the track below.

Chuck (Modeling Central Japan in September, 1964)

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It sees to me that I read somewhere that one or more railroads converted their double track mains to single track through the middle of double track tunnels to accommodate additional train height. The middle of the tunnel being higher than the area toward the sides. I believe at least one used a gantlet track arrangement to do so.

5

for a short while after the merger, the area west of the Gallizin tunnel portals was littered with automobile roofs and luggage racks.

grizlump

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Re: the “mouse ears” in tunnels:

About 15 or 20 years ago I had occasion to do some photography related to the cutting of “mouse ears” into the roofs of tunnels on the ex-WP line through the Feather River canyon on into Oakland. The ears were cut using a big rotating wheel (maybe about 8-10’ diameter) studded with carbide teeth. The machine was mounted on a flat car and shoved into the tunnel ahead of several other cars and a loco. My recollection of the drawings I saw is that the cuts were made to provide a 3" clearance around the corners of stacked hi-cube boxes. The amount of cutting was entirely based on this dimension, so it might be deeper here, shallower there, and asymmetrical elsewhere.

I was lucky to be able to see the operation first-hand inside tunnel #1. This tunnel is concrete-lined. When the cutter hit re-bar, the guys got out the torches. The teeth weren’t happy working on steel.

Ed

7

The track near me “sand patch (CSX)” has a tunnel, but just the small double stacks can go under. They are currently making it bigger for the bigger double stacks.

Here’s some older shots of some tunnels.

http://cs.trains.com/TRCCS/themes/trc/utility/[IMGhttp://i119.photobucket.com/albums/o144/robby_79/003-6.jpg[/IMG]:550:0]

http://cs.trains.com/TRCCS/themes/trc/utility/[IMGhttp://i119.photobucket.com/albums/o144/robby_79/003-11.jpg[/IMG]:550:0]

http://cs.trains.com/TRCCS/themes/trc/utility/[IMGhttp://i119.photobucket.com/albums/o144/robby_79/003-7.jpg[/IMG]:550:0]

8

Baltimore MD had a couple examples of a double track tunnel with a freight gantlet.

The B&P Tunnel (fromer PRR now Amtrak) had a gantlet track at the curve near Pennsylvania Avenue.

The B&O’s Howard Street Tunnel had a gantlet to allow passage of high freight cars. In steam days, third-rail-powered electric locomotives were used to pull eastward trains upgrade through the tunnel. The third rail shoes were mounted on arms that could reach the third rail from the gantlet. Later (around 1960?) the tunnel was single tracked.

The Howard St. tunnel was the site of the first mainline electrification in the U.S. Some B&O men used to like to point out to the Pennsy men that while the PRR"s electrification might be longer, the B&O’s was first…