Steam & Excursion > Steam Files PRR #7

Today lets take a look at a PRR M1 class 4-8-2.

These locomotives were designed by two of PRR's finest locomotive designers and produced from 1923 to 1930 with a total of 301 built (201 M1's and 100 M1a's) 
The M1a's had table grates, two air compressors and Worthington feed water heaters.
In 1946 40 were converted to M1b with an increase of steam pressure from 250 to 270 psi, had their fireboxes extened slightly and were equipped with water circulators.

James Tureaud Wallis and William F. Kiesel, Jr. were the brains behind the design, which was an offshoot of the I1 Decapod.

They were extremely successful locomoives for the PRR and operated until replaced by diesels. Twenty M1's and ten M1a's were assigned to passenger duties, primarily between Harrisburg and Columbus, OH.

Most had Dupont-Simplex Type B from Standard Stoker, some had the Duplex Type D-1 from Locomotive Stoker Company.

Specs: M1a - Cylinders 27 x30, Drivers 72 inches, Boiler Pressure 250 psi, Tractive Effort 64,550 lbs.
Factor of Adhesion: 4.20

Tender Capacity: 22,090 gallons
Coal Capacity: 31- 1/2 short tons.

Altoona built the first one in 1923 and the remainder were either Baldwin or Lima products, (excepting 25 at Juniata in 1930)
The 6789 as seen here is an M1a built in 1930 by Lima.

As has been noted before. Over the last 25 years or so, I've collected many images of steam engines sent by "friends, neighbors, co-workers and miscellaneous group threads". Some identify the photographer and source, and many do not. They were simply "really cool" images I dumped into my image files and promptly forgot. Lately I've tried to cleanup, clean out and organize some of my files and started looking closer at some of the old steam engine pictures.

So, I thought maybe I'd post some. If anyone knows proper photo credits or has any additional information or corrections, that would be appreciated.

I do not know anything about the photogrpaher, date or location of this image.

 



Edited 3 time(s). Last edit at 06/25/25 07:10 by train1275.

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'Really enjoying your shared photos.   Thanks!

Greg Stadter
Phoenix, AZ

Your steam photos are especially appreciated.
Bob

Great information. I always wondered why the PRR developed such a nice high horsepower locomotive equipped with a dome throttle instead of a front end throttle.

The PRR M1 Mountains have always been among my favorite locomotives, and that is an excellent roster shot of a fine example. They were a mainstay of so much of Pennsy's operations, and performed well over many years of service. They were big, powerful, versatile, and up to the job. As with other PRR power, conservatively engineered and full of traditional PRR design philosophy, but with a little stretching of the envelope too.

A very nice photo of a classic and important locomotive - thanks.

MC

The PRR M1 was one of my dads favorite steam locos.  He has fond memories seeing these on coal trains running the PRR Elmira Branch.