I am interested in the history of EMD’s #291 (A-B-B-A) demonstrator set built in 1946. How long did these sets do their thing before being sold off? Which railroads tested them (by unit # preferably) and did 291 aver get split into A-B, A-B-A or A-B-B sets before sell-off?
Many thanks.
“General Motors’ F-UNITS - The Locomotives that Revolutionized Railroading” by Daniel J. Mulhern and John R. Taibi has some information on these units, not sure (I have the book at home) how much detail they go into as far as where they went. I do know they were really “F2’s”. In 1945 GM designed a new 1500 hp F-unit to be the replacement for the 1350 horsepower FT diesel, with a new longer carbody and other changes. The new diesel used the same diesel motor as the FT, but with a new generator that allowed greater horsepower to be produced. Unfortunately, in 1945 they couldn’t get the new improved generator they needed in time, so they made the demonstrator set using all the new changes but with the motor and generator from the FT. Several railroads ordered these engines, which were called “F2’s”. When the generators became available, GM immediately started putting them in the new diesels, and changed the name to “F3”. Externally the F2 and F3 were identical.
The Order number, date, serial number, road, and road number is below for the orginal F3A BB A set built as the EMD demo units. Looks like a part of the set went to TPW.
Thanks to EMD unofficial page data.
They are listed as being built in July of 1945. I am not sure when the demo’s hit the road.
Order# Date Ser# Dem Road#
E673A 07.45 3370 F3A EMDX 291A1 1 . to TPW 100A
E673A 07.45 3371 F3A EMDX 291A2 1 . .
E673B 07.45 3372 F3B EMDX 291B1 1(2) . to TPW 100B
E673B 07.45 3373:1 F3B EMDX 291B2 1(2) . Rebuilt to 754B1
E673A 07.45 3371 F3A EMDX 291A2 1 . . was wrecked 12/25/46.
BTW I was thinking of the three unit F3 demonstrators that toured in 1946, which were really F2’s. 291 was something a little later. [
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EMD 291 was the original F3 built in July 1945. There were no other F2 or F3 demonstrators prior to the 291. What are you writing about here? [:)]
In mid-late 1945 EMD thought it was all set to replace the 1350 hp FT with a new larger 1500 hp F-unit. Unfortunately, a generator needed to create the additional horsepower ended up not being available until late 1946. So EMD created an A-B-A demonstrator set using the new carbodies etc. to show the new engine to the railroads, but had to use the old generators so the units only produced 1350 hp each.
Some railroads did order and receive loco’s built to these specifications, which came to be known as F-2’s. When the generator became available in late 1946, GM began using the new 1500 hp engines, these engines were F-3’s. I believe this is when GM made the A-B-B-A demonstrator set no. 291. The earlier A-B-A set was no. 754 (see link).
The 291 set was released by EMD on 7/31/45. One unit of the 291 set became the B unit in the 754 ABA set. The 2 A units in the 754 set were built in 9/46. See http://community-2.webtv.net/ajkristopans/FREIGHTCABUNITS/index.html for builders dates. The 291 was the earlier set. The 754 was the later demonstrator set.
Did the F3 Demonstrators have steam generators, sorry but could not resist?
I know 754 did. The “F-units” book I talked about 754 being used to demonstrate the F3’s passenger capabilities. Not sure about 291??
BTW that book basically covers F’s in chronological order (FT’s then F2’s then F3’s etc.) so since 754 was mentioned in that book before 291I jumped to the conclusion that 754 had been built first. [:(]