Nostalgia & History > Wheel and Track Standards, 1903

Just thought I'd post this for anyone who ever wondered but didn't dare to ask.

-John



Edited 1 time(s). Last edit at 10/31/14 14:58 by LarryDoyle.

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Hopefully I'm not going to slap my head when someone tells me, but what does MCB stand for? And what document does this come from?

Greg

Greg Ramsey
Las Vegas, NV

The Master Car Builders Association was a predecessor to the American Railroad Association which was a predecessor to the American Association of Railroads.

This is from MCB Plate 12 of 1903, as published in the Car Builders Dictionary of 1909. I've changed the title to reflect the date.

I don't think they've changed too much since then.

-John



Edited 1 time(s). Last edit at 10/31/14 14:57 by LarryDoyle.

MCB=Master Car Builders. These are all ideal dimensions. What tolerance is out there in the real world? Looks like track gauge 5' 3/8" would drop the wheels between the rails?

Yes, thank you for not making me go duh. :-)

Yes, the ideal specs are all essentially the same. They have to be so that old stuff can still run on modern track. But I think I'm going to steal the graphic as an intro into "gage" section of my Navy track inspectors class.

To know the tolerances, you need to know the class of the track.

Greg

Greg Ramsey
Las Vegas, NV



Edited 1 time(s). Last edit at 10/31/14 15:15 by atsfm177.

Railpax71 Wrote:
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> MCB=Master Car Builders. These are all ideal
> dimensions. What tolerance is out there in the
> real world? Looks like track gauge 5' 3/8" would
> drop the wheels between the rails?

Depends upon how fast you want to go.

For exempted track under today's FRA standards, the lowest class, the gauge can be from (no minimum standard) to 58 1/4". 10 mph or less.

For class 5 track, 56" to 57 1/2", allowing a speed of 79 mph freight or 89 mph passenger.

-John

Before everyone gets all wound up about these being "FRA or ICC track standards" of the day, they were merely recommendations by the MCB. Although just about all the RRs followed them, they didn't have to. The FRA didn't get involved until the 1970s, after which time they became codified to the point of compliance no longer being voluntary.

Railpax71 Wrote:
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> Looks like track gauge 5' 3/8" would
> drop the wheels between the rails?

Look at it more carefully: It reads Track Gauge 4'- 8 1/2" and Gauge Over All (Over outsides of wheel faces) 5'-4 3/8".

Mark



Edited 1 time(s). Last edit at 10/31/14 20:09 by mwbridgwater.

Not only these wheel and rail gauge dimensions are "backward compatible, so are the coupler height and knuckle dimensions, and the basic air brakes
compatible going back through the decades.
What has changed is the frame strength, wheel and bearing quality and capacity, knuckle strength, etc. that may allow a SD-70 to couple into, release the air on, and move a 1903 car, but you could not put it in a 100-car train of 263,000 lb cars without some interesting events.

I'm guessing the 1903 car would grow in length to a certain point...
Gonut