What does it mean?

[Paul Erena]

I have begun exploring the amazing world of live steam with my kids. One thing I noticed on many locomotives was that next to the cab number there is often a fraction or a percentage attached to the side of the engine. What is this number- what does it mean? Do all steamers have this? Thanks for clearing this up for me.

[nanaimo73]

Union Pacific 844 says FEF-3 (class) 80 (driver diameter) 25/32 (cylinder size?) 266 (266,000 weight on drivers ?)
http://www.rrpicturearchives.net/showPicture.aspx?id=167554

Some Canadian locomotives had the tractive effort on them, 844 would have a 63 for 63,800 lbs.

[CSSHEGEWISCH]

Southern had similar numbers on the engineer's side of the cab of its steam locomotives. As mentioned above, they are probably related to driver and cylinder size. The numbers were not on the fireman's side, all he got to see was the coal capacity on the tender.

Welcome to the forums[:D] You will find us variously entertaining, opinionated, argumentative[soapbox] and even informative[^] Enjoy your visits.

[West Coast S]

Along with driver and cylinder info, some roads (Southern and Southern Pacific for example) would designate a superheater equipped engine with a "S".

This practice was fairly common and unusually uniform regardless of road.

Dave

[PBenham]

On Canadian National steamers the percentage was the percentage of 100,000 lbs tractive effort. So, If a CN engine developed 125,000lbs tractive force, it would have had 125% stenciled on the bottom edge of the cab. Most other railroads had those figures in employees timetables, rather than clutter up the cab side with a lot of extraneous details.There were and are exceptions to this, like UP. If you're freelancing, the data on the cab side is entirely up to you! If you model a specific engine, then try to locate books and photos of the engine you'll model. Then go from there.

[egmurphy]

QUOTE: Originally posted by Paul Erena

.... One thing I noticed on many locomotives was that next to the cab number there is often a fraction or a percentage attached to the side of the engine. What is this number- what does it mean? Do all steamers have this? ....

I think Pete probably has the most likely answer. I know that down here NdeM steam locos also had this xx% sign to indicate tractive effort in thousands of lbs.

Do all steamers have it? No, it just depends on the practice of the particular railroad.

Regards

Ed

[Anonymous]

Hey Paul, nanaimo73 was right on for the UP. FEF-3 means four-eight-four third series. 80 is driver diameter in inches. 25/32 is bore , 25" and stroke, 32" and 266,000 lbs. on the drivers.

Look at the UP's 3985 cab. It has 4-6-6-4-4-69 21-21/32 404

Any guesses?? 4-6-6-4 is the class, 4th series, 69" dia. drivers, two sets of cylinders (front engine - articulated, and back engine rigid to the frame) both 21" in diameter (hence 21-21) with a 32 inch stroke for both, and 404,000 lbs. weight on the drivers.

UP's 2-10-2s bore T-T-T on the cab for "two-ten-two" class.
The UP sure as heck wasn't going to call 'em "Santa Fe" class, as most 2-10-2s were known!

Now for the trivia: On most US railroad 2-8-2s were called Mikados or Mikes. From 1942 to the end of steam U.P. 2-8-2s Cab side data started with MacA ; e.g. "MacA - 63 26/28 214 ". (63 is driver dia., no series number ) With the outbreak of the US war in the Pacific, UP renamed their 2-8-2s MacArthur class for Gen. Douglas MacArthur , dropping the Mikado name as it was of Japanese origin.

How about this UP one ??? 2-8-8-2 57 25-39/32 485 ??

This was "compound articulated" with 2-8-8-2 wheel arrangement, 57" drivers, rear cylinders 25" dia. and front cylinders 39" dia. - both with a 32 inch stroke and 485,000 lbs. on the drivers. In "compounds" high-pressure steam from the boiler went first to the rear 'High pressure" cylinders which were smaller and was then exhausted from them into the larger diameter front cylinders at a much lower pressure and then exhausted out the stack. Because the steam was at lower pressure (fewer pounds per square inch ) it had to push against a

larger piston (more square inches) to get the same driving force to the drivers.. questions ?? …these were actually old N&W engines the UP acquired for war time service and they'd only go about 20 miles an hour, but boy could they pull !!

Regrettably there are no UP 2-8-2s or 2-8-8-2s in operation , nor any compounds. At some point though you'll see pictures of these engines as your kids' interest in steam grows…good luck !

How about … T-M-I 4 U ?? (too-much-information for you ??)