Trains.com

Historical Loading Gauges of North American Railroads

2792 views
18 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    May 2020
  • 16 posts
Historical Loading Gauges of North American Railroads
Posted by L-105 on Tuesday, June 29, 2021 4:07 PM
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 know of an excellent resource for British historical loading gauges, including GWR 7ft broad gauge, complete with sketches here:
 
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.
  • Member since
    February 2005
  • 2,026 posts
Posted by timz on Tuesday, June 29, 2021 4:23 PM

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.

  • Member since
    February 2002
  • From: Mpls/St.Paul
  • 12,376 posts
Posted by wjstix on Wednesday, June 30, 2021 11:02 AM

L-105
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.

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.

Stix
  • Member since
    May 2004
  • 6,874 posts
Posted by 7j43k on Friday, July 2, 2021 8:20 PM

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.

Here's the one for Washington State:

There is also this:

https://en.wikipedia.org/wiki/Loading_gauge

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.

Interesting.

 

Ed

 

 

 

 

 

  • Member since
    May 2020
  • 16 posts
Posted by L-105 on Saturday, July 3, 2021 12:24 PM
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
 
C&O H-8 16ft 7 inches tall and 11ft 2 inches wide
 
Virginian AE 16ft 7 1/2 inches tall and 12ft wide
 
DM&IR M-3/M-4 16ft 3 inches tall and 11ft 3 inches across running boards
 
There are many more examples as well. 
  • Member since
    September 2003
  • 17,647 posts
Posted by Overmod on Saturday, July 3, 2021 2:54 PM

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.

  • Member since
    February 2005
  • 2,026 posts
Posted by timz on Tuesday, July 6, 2021 12:27 PM

L-105
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.

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.

  • Member since
    March 2016
  • From: Burbank IL (near Clearing)
  • 12,502 posts
Posted by CSSHEGEWISCH on Wednesday, July 7, 2021 10:29 AM

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.

The daily commute is part of everyday life but I get two rides a day out of it. Paul
  • Member since
    January 2019
  • 1,044 posts
Posted by Erik_Mag on Wednesday, July 7, 2021 10:14 PM

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.

  • Member since
    February 2005
  • 2,026 posts
Posted by timz on Thursday, July 8, 2021 1:09 PM

How wide were they? They were the usual 10 ft wide when they were new, and CNW expanded them?

  • Member since
    September 2003
  • 17,647 posts
Posted by Overmod on Thursday, July 8, 2021 2:36 PM

Merchandise Mart, no?

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...

  • Member since
    January 2019
  • 1,044 posts
Posted by Erik_Mag on Thursday, July 8, 2021 10:01 PM

Merchandise Mart it is...

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.

  • Member since
    February 2005
  • 2,026 posts
Posted by timz on Saturday, July 10, 2021 6:42 PM

Wikipedia says the Pentagon has 6.5 million sq feet total, compared to 4 million for the Merchandise Mart.

  • Member since
    September 2003
  • 17,647 posts
Posted by Overmod on Saturday, July 10, 2021 8:49 PM

timz
Wikipedia says the Pentagon has 6.5 million sq feet total, compared to 4 million for the Merchandise Mart.

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.

  • Member since
    January 2019
  • 1,044 posts
Posted by Erik_Mag on Saturday, July 10, 2021 10:51 PM

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.

  • Member since
    December 2007
  • From: Georgia USA SW of Atlanta
  • 10,454 posts
Posted by blue streak 1 on Friday, July 16, 2021 10:54 PM

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.?

  • Member since
    March 2016
  • From: Burbank IL (near Clearing)
  • 12,502 posts
Posted by CSSHEGEWISCH on Saturday, July 17, 2021 9:55 AM

Speaking of curves, the IRT had an interesting solution at the South Ferry station:

https://www.nycsubway.org/perl/show?70806 

The daily commute is part of everyday life but I get two rides a day out of it. Paul
  • Member since
    September 2011
  • 5,382 posts
Posted by MidlandMike on Saturday, July 17, 2021 10:57 PM

blue streak 1
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 ?

I figured 80 foot center pins and got 1.4 feet overhang at center.  Radius=573.4'

r - sq rt (r sq - 40 sq)

  • Member since
    May 2003
  • From: US
  • 21,156 posts
Posted by BaltACD on Sunday, July 18, 2021 11:46 PM

MidlandMike
 
blue streak 1
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 ? 

I figured 80 foot center pins and got 1.4 feet overhang at center.  Radius=573.4'

r - sq rt (r sq - 40 sq)

Standard Car width is 10 feet 6 inches

For Autoracks which have exterior length of 93 feet - the width of the car is 9 feet 6 inches

As listed in UMLER.

Join our Community!

Our community is FREE to join. To participate you must either login or register for an account.

Search the Community

Newsletter Sign-Up

By signing up you may also receive occasional reader surveys and special offers from Trains magazine.Please view our privacy policy