Length of FT vs F

Wheelbase Chart

From that chart, it looks like the FT is shorter

Just did a quick search and American-Rails.com gave these lengths.

FTA: 48'3"

F3A: 50'8"

@CAPPilot posted:

Just did a quick search and American-Rails.com gave these lengths.

FTA: 48'3"

F3A: 50'8"

Those length would be measured where? Over coupler pulling faces? Underframe length?

@Hot Water posted:

Those length would be measured where? Over coupler pulling faces? Underframe length?

Jack,

I assume those lengths were measured the same way so the comparison, now from two different sources, holds to answer the OP's question.

@joe krasko posted:

To settle an argument  is the FT the same length as a standard F  unit

No. FT units are shorter.

(not FP or FL9)...thanks   joe

Thanks to John and Ron for the info....joe

Yes FTs were shorter. The difference is noticeable at the rear of the FTs. If you look at a sideview of an FT, the rear truck is much closer to the end than the front (pilot) truck is from the front. The trucks on the B-units are offset too. As originally designed, the A and B units were only to be connected to each other with a drawbar, so there was only room left for a coupler on one end. All later F's were symmetrical, both trucks were the same distance from the end.

@wjstix posted:

Yes FTs were shorter. The difference is noticeable at the rear of the FTs. If you look at a sideview of an FT, the rear truck is much closer to the end than the front (pilot) truck is from the front. The trucks on the B-units are offset too. As originally designed, the A and B units were only to be connected to each other with a drawbar, so there was only room left for a coupler on one end. All later F's were symmetrical, both trucks were the same distance from the end.

Now we know the whole story.

In EMC's basic design, the two draw-bar-connected units had to be operated as a set, because the batteries for cranking both diesel engines were all in the "B' unit. Santa Fe did not like this arrangement and recommended stand-alone operating capability, which was a "bombshell for Electro-Motive" because now they had to figure out a way to attach a coupler and draft gear to the short end of the "B"unit where the drawbar connection had been (see The Revolutionary Diesel EMC's FT by Diesel Era, page 12). Electro-Motive came up with an "S"-shaped coupler drawbar.

When the FT model was being designed, in about 1937, the only suitable coupler draft gear assembly available was that which was being used on the rear of large steam locomotive tenders. Thus, there had to be sufficient spacing between the truck and the front pilot of the front "section" (the term 'unit' had not been used yet) and the rear of the rear "section". As a result the underframe of the FT was "short" so that a draw-bar coupled 2700 HP set would also fit on the most common 90 foot turntables of the era.

When the Santa Fe specified that the front "section" and rear "section" NOT have drawbar connections, the Minor Draft Gear Co. eventually came up with a shorter, high strength draft gear assembly in order for couplers to be installed between the front and rear "sections".

When the F2, F3, F5, and F7 models were designed, during the later years of WWII, the underframe was lengthened and the Minor draft gear and couplers were used at both ends of all models. With the longer underframe the batteries were also included in both the A Units and B Units.

A problem with the original FT design was your only options were to run one A-B set (2700 HP) or two A-B sets coupled together back-to-back (5400 HP). The rule of thumb was for mainline trains, you needed around 4000 HP...so one wasn't enough, two sets were too much.

GM came up with the FTSB ("FT - Short Booster") that had drawbar connections at each end, so it could sandwich between two FT A units for an A-B-A set of 4050 HP.

However, several railroads just bought F2 (and later, F3) A units in 1945-47 and coupled them to their FT A-B sets to make what some railroads called an "FT-2" A-B-A set.

There were a lot of things that differentiated the FT from all later F-series locomotives.  Some were appearance items, but the following features were also changed on the F2 through F9:

• The pilot cutaway.
• the side-facing Brakeman seat was moved to the back wall on the F2, facing forward, and on later models moved again to a position beside the Fireman seat.
• Belt-driven radiator fans.
• Manual fan clutch (the Fireman's duty).
• Manual radiator shutters (also Fireman's duty).
• 8-EL air brake schedule, replaced by 24-RL on later models.
• Side window in the cab had no swiveling vent pane, as did later models.

The FT once it went into revenue service, gave EMD a lot of ideas for improvement of its postwar freight units.

Very interesting and informative thread.  Thank you all that contributed.

However, several railroads just bought F2 (and later, F3) A units in 1945-47 and coupled them to their FT A-B sets to make what some railroads called an "FT-2" A-B-A set.

The NYO&W bought 3 F3As (501-503) specifically for this purpose. They also ran these F3s solo.

Chris

LVHR