Can someone tell me what engine the Great Northern used on Thierry Empire Builder routes in the late 1950's and early 60's. Thanks!
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From the Great Northern Historical Society, it appears from 1950 to 1967 EMD F units, F3 and F7s, re-geared and equipped with steam generators pulled The Empire Builder.
Thanks Joe! I road that route in 1959 when I was 11 years old. Fun trip but I did not know what the engine was.
Your welcome. 1959 F units in Omaha Orange, Pullman Green with the gold stripes.
A-B-B-A mixed F3s and F7s in the late 1950s, A-B-A consists in the earlier 1950s.
You are probably aware that the original diesels for the Empire Builder were pairs of back-to-back E7A's. The change to A-B-A F3's provided 4500 hp instead of 4000 and increased the steam generator capacity. GN passenger F3 and F7 units did not have dynamic braking.
Yes, like many 1940s railroads, GN found that E-units with their A-1-A trucks with unpowered center wheels did poorly in the mountains, so switched to F-units by about 1950. Burlington Route E-units generally pulled the train from St. Paul to Chicago.
@wjstix posted:Yes, like many 1940s railroads, GN found that E-units with their A-1-A trucks with unpowered center wheels did poorly in the mountains,
Please explain what "A-1-A trucks with unpowered center wheels" have to do with poor performance on mountain grades.
so switched to F-units by about 1950. Burlington Route E-units generally pulled the train from St. Paul to Chicago.
F-units have "B" trucks - each truck has two axles, each powered. All the locomotive's weight is on the powered axles. With E-units, the trucks have three axles, and the center one is an unpowered "idler" (so "A-1-A"). Although this provides a very smooth ride at high speeds, it does mean only 2/3rds of the engine's weight is on the powered axles, which diminishes it's tractive effort. On flat land, that 'dead weight' didn't matter, but when E-units tried to pull trains up mountain grades, it often caused the motors to overheat and fail.
@wjstix posted:F-units have "B" trucks - each truck has two axles, each powered. All the locomotive's weight is on the powered axles. With E-units, the trucks have three axles, and the center one is an unpowered "idler" (so "A-1-A"). Although this provides a very smooth ride at high speeds, it does mean only 2/3rds of the engine's weight is on the powered axles, which diminishes it's tractive effort. On flat land, that 'dead weight' didn't matter, but when E-units tried to pull trains up mountain grades, it often caused the motors to overheat and fail.
Sorry but, your explanation has nothing to do with why the traction motors on E Units would "overheat" at slow speeds. The real issues was, the E Unit A-1-A trucks were equipped with 36" diameter wheels, thus the need for high speed gear ratios for passenger train speeds (the highest speed gear ratio was 55:22 for 117 MPH). The F Unit "Blomberg" two axle trucks had 40" diameter wheels, and thus could operate at VERY slow speeds (62:15 gear ratios) without damaging the traction motors. Weight on drive wheels was NOT a factor for overheating traction motors at slow speeds.
Anyway . . . . . . Great Northern found good use for its E7's on its short haul passenger trains, so all turned out well.
Yes, I found a pic online that shows three GN E-units - in two different paint schemes - at the roundhouse that was inside the wye east of St Paul Union Depot.
https://www.railpictures.net/viewphoto.php?id=414703&nseq=57
Not sure of the date, but since none of the engines are in the 'simplified' scheme, I'd guess it's 1962 or a bit earlier.
As a kid I got to ride from Minneapolis to Superior WI on GN's Badger pulled by an E-unit...unfortunately didn't record the engine number!
