Does anyone have any information, or know any resources detailing precisely what the loading gauges of various US railroads during 1920s, 30s and 40s actually were?
I can only get a rough idea of what the allowable clearances of various US railroads were by looking at locomotive diagrams and specifications and checking the maximum heights and widths of the locomotive, but these are not necessarily representative of the absolute maximum clearances of a railroad.
For instance on the Pennsylvania Railroad the J1s were 16ft 5 1/2 inches tall by 11ft 3 inches wide and the Northern Pacific #5001-5011 Z-5s were 17ft 2 inches to the top of the stack by 11ft 6 inches wide.
I know that the New York Central and Baltimore and Ohio had more restrictive clearances relative to some other US railroads, whilst the Erie was reputedly the most generous.
I have several issues of Railway Line Clearances, which came out quarterly and showed the maximum sizes of cars allowed on each line, presumably meaning the maximum allowed without some sort of special handling.
It would say that between points A and B cars could be so many feet-inches wide at so many feet-inches above top of rail. Obvious question: if cars are allowed to be 15 ft 3 in tall, but not allowed to be 15 ft 6 in tall, what does that tell you about the lowest overhead bridge? I assume it’s more than 15 ft 6 in above top of rail, but how much more? No idea about that.
By the way – passenger cars were (and still are, AFAIK) 10 ft 0 in wide at floor level. So high platforms are about 5.6 feet from the track centerline. So was a PRR 2-10-4 allowed to pass the Johnstown platforms on the adjacent track? I suspect it was, but I haven’t checked the timetable. Its maximum width was likely at a point more than 45 inches above top of rail.
The eastern railroads were often restricted due to tunnels built in the 19th century when equipment was much smaller, the same problem faced by the British railways. In the midwest and west, it was much less of an issue.
The Erie was originally built to 6’ gauge IIRC, so would have been built with larger right-of-way clearances because of that.
I know Washington (state) and Oregon set clearances for railroads, as I have a copy of each of the documents. These worked “inwards”, detailing the closest a thing (building, tunnel, pole, etc.) could be to the tracks.
They go the other direction: how “far” from the tracks. The classic for this is the Plate diagrams in the Official Railway Equipment Register, applying to freight cars.
Logically, they should mate. Of course, the State standards might be accounting for clearance of riders on cars, while the other one isn’t.
I’m familiar with the AAR clearance plates and have the specifications on all of them. I’m confused about the seemingly contradictory maximum clearances set by the AAR plates and the fact that the extreme heights and widths of many steam locomotives exceed them. It’s hard to believe the clearances would have been reduced in size since the steam era, as the general progression has been to move to increasingly generous clearances.
For example the Union Pacific Big Boy is 16ft 2 1/2 inches tall by 11ft wide. It’s width exceeds all the AAR clearance plates (10ft 8 inches wide, even the newer ones) by 4 inches. Moreover its height exceeds the most widespread plates B and C by 13 1/2 and 8 1/2 inches respectively. So how does this work?
The Big Boy is by no means unique in this regard, along with the examples given in the first post, others include:
ATSF 5001 class 16ft tall, 11ft wide across the cylinders and 12ft 2 inches across window awnings
AAR is interested in car clearance for interchange on ‘the general system of transportation’. That is not the maximum or high/wide clearance for a particular route or railroad – just the minimum required.
The plates don’t “set maximum clearances”. Forget the AAR plates, if they confuse you. They’re not intended to limit the size of anything.
Many RRs in Railway Line Clearances were willing to accept loads 22 feet tall and 11 or 12 feet wide on some of their lines. One short line allowed 15 feet wide in 1954, and another allowed 16 feet wide. (So they said, anyway.)
For some reason UP showed a 20-ft limit, but that was the limit Denver to Granger, 20 ft tall by 12 ft wide.
It should be noted that many larger steam locomotives were restricted to a given operating area because of their size and weight. Even now, I still see cars that are stenciled “Exceeds Plate C (or something else)”. This would indicate that they are restricted to certain lines.
Back in the early 1930’s, the C&NW had several extra-wide boxcars that were oly used between the Chicago Merchant Mart (name?) and the freight house at Proviso Yard. Main reason for the extra width was to allow quicker loading and unloading.
When I was a kid in the early Sixties, the World Book encyclopedia and other publications listed this as ‘the largest building in the world’ by floor space…
As for the C&NW boxcars, the write-up in Martin Stevers book, Steel Trails, just mentioned that the bodies were wider than standard for interchange. The book also mentioned that the merchandise was loaded on four wheel carts that were then loaded in the box cars. When arriving at the Proviso freight house, the carts would be wheeled out of the box car and then over to the designated outgoing box car.
This is why you shouldn’t trust the kids’ encyclopedia when you’re at a young and uneducated age.
Largest when built in 1930, but eclipsed by the Pentagon in 1943. I believe the property was effectively expanded in the late '70s to about 6.2 million sq.ft. but that’s still smaller…
I’m told the Mart is now only the forty-fourth largest in terms of floor space. Sic transit and all that.
Not quite sure about floor space - Boeing’s wide body assembly building is, IIRC, in at least the top three buildings in terms of interior volume. The pllanes look small when viewed from the walkway just under the roof.
This may be completely wrong. Do not have time to do the math. About plate clearances. If RR has a 89 foot freight car the center pins of each truck is about 82 feet between centers. So for a curve of say 10 degrees how much would the 41 foot distance to the center of the car from truck pins deviate from the center of the track ?
Now compare a 90 foot 4-8-4 whose 45 foot center is between driving axels 2 and 3. On that same 10 degree curve how far will the front and cab overhang to the outside from the track center?
Are the oversized locos wider at the loco center ? If so is the front and cab tapered to meet the plate clearance number ?
It would appear that RRs will need more clearances on any track with curves the tighter the curve the more the clearance needed. Wonder if some warehouses built with curve tracks do not take this into consideration with probable consequences.?
