NYC DFA-1a & DFB-1a


NYC 1600/2400/2401/1601 (Electro-Motive, June 1944) was the first of two, four-section (A-B-B-A) 5400 hp FT locomotives delivered to the New York Central Railroad.  They were classed as DFA-1a (A-Unit) and DFB-1a (B-Unit).





Originally EMC (so named until January 1st 1941 when they became EMD) designated the A-Unit and B-Unit as: first section and second section, respectively.  Why did they do this, after all there were cab-equipped A-Units and cab-less booster B-Units in their passenger Model E line already in service?


The first & second sections together were considered one 2700 hp locomotive, the Model F.  It was designed in two sections because the new, longer sixteen cylinder 567 prime mover and generator (two each, like the earlier twelve cylinder 567 passenger Model E) would result in a car body that was too long and structurally unsound.  So, this was solved by “hinging” the locomotive and placing one prime mover and generator set in each car body.  These sections rode on four wheel trucks, each axle with a traction motor (B-B).  I like to think of it as an articulated locomotive, although I’m sure this is not purely proper.


The two sections were connected by a drawbar.  They were not separable except for heavy servicing at a locomotive backshop.  Two such locomotives could be multiple-unit’d together to form a four-section 5400 hp locomotive.  Many were sold this way to the early buyers of EMC’s Glamour Girl.


As I understand it, General Motors marketed its 2700 hp locomotive as an efficient, modern alternative to the 2-10-2 steam locomotive of which, by 1939, many were ripe for replacing nationwide.  The drag freight era had passed in the mid-to-late-twenties and the low-drivered Santa Fe type was no longer favoured as mainline freight power.  It was the fast freight era and the Model F offered outstanding tractive effort in an efficient fast-freight package.


In a 1942 report from the Baltimore & Ohio describing their new diesel freighters, the term “sections” are still used.  However, my General Motors book (Instruction Manual 254, 5400 HP Diesel Freight Locomotives) published in June of 1944 calls them units.  No doubt this change was greatly influenced by the Atchison Topeka & Santa Fe Railway, a very early buyer of the Model F.


Early in 1940 the Santa Fe wanted Electro-Motive to make each section as a stand-alone, self-contained 1350 hp unit.  They apparently saw the operational flexibility of mu’ing power as needed and being a potentially large customer, EMD agreed to do it.  This involved, among many other smaller changes, designing draft-gearless couplers to replace the drawbar, providing batteries in each unit (the first section had them only), adding hostler controls for the booster unit, adding doors and separate diaphragms at the car body ends that were previously open and protected by one connected canvass diaphragm.  Every one of the 80 four-unit (320 units total) 5400 hp locomotives were delivered to the Santa Fe this way.  A few other railroads ordered them like this (Denver Rio Grande & Western, Missouri Pacific, Southern Railway), but they all also had drawbar-equipped versions too.

By about 1943, the Model F (as it was always named in the EMD Engineering Department) started to be called the FT by the Sales Department.  The reasons why are lost to time.


In spite of Santa Fe’s pioneering freight diesel concepts, most (about 2/3) FT’s were delivered as drawbar-equipped sections, some even as fully drawbar A-B-B-A consists.  NYC 1600/2400/2401/1601 had drawbars between the A & B-Units and regular Type E couplers between the B-Units and at the pilots of the A-Units.  Photographs show that the NYC operated them as two-section 2700 hp locomotives as well.


The EMC Model F Demonstrator 103/103A (four-section 5400 hp locomotive) was tested over New York Central rails in September of 1940.  But, it was not until early 1944 before the Railroad placed an order for two, four-section 5400 hp locomotive sets – the War Production Board had halted Model F construction for some months in favour of U.S. Navy requirements, only allowing FT production to resume in the Summer of 1943.


By then, wartime austerity had removed a lot of glamour from the FT.  Gone were the chrome trim rings around the headlights, the stainless steel kick-plates below the entry doors, and the magnificently colorful paint jobs.  The DFA-1a and DFB-1b’s were delivered in tuxedo black overall.  On the nose was a simple motif of six white lines with the new red-backed NYC oval.  Lightning stripes were some many months in the future (first appearing in March of 1945 on EMD E7 passenger locomotives) and, to me at least, this was a representation of New York Central’s six-track mainline.


Oddly, the only option applied, aside from the reflectorized numbers on the nose, was late production dynamic brakes (rail-fan: Phase III).  Perhaps these were useful in a few places (like the Berkshire Hills on the Boston & Albany), but not so for the mostly flat Water Level Route.  I think it was probably easier for EMD to build them one way and easier for the War Production Board to release them that way.


In 1944, the four 2700 hp locomotives were not going to change the operating bottom line.  However, they ultimately convinced the Railroad, steeped in the finest steam locomotive design and operating tradition, that times were significantly changing.

Like my EMC 103/103A Demonstrator of last year, this model of the NYC mainline diesel freight pioneer is based on the HO Scale Stewart FT.  They are no longer offered, but quite a number of them are often available through E-Bay.  This build was much easier since I did not need to alter the rivet strips on the car bodies; the Stewart model captures these very well for a regular production EMD FT.  The rest of the construction was along the same lines as the 103/103A build.


DCC/sound is my standard Soundtraxx Tsunami 2 EMD Diesel.  Since the two units will not be separated I installed only one decoder on top of the motor in the cab unit where there is also a speaker.  A second speaker was installed inside the motor-less B-Unit.  I programmed the decoder to use the Dual 567 option – a trick to provide the sound of two prime movers while using only one decoder.  On start-up, each prime mover fires separately and this sounds really good.  An additional advantage to using only one motor/decoder is that I get sixteen wheel pick-up by wiring the wheels of the unpowered B-unit to the decoder.


The Microscale decal set (87-49) does not include the nose motif, although it was useful for the lettering, numbers, and the red oval.  I made the nose stripes by first spraying the area Testors Insignia White on top of Tamiya Fine Surface Primer.  Then I used .50mm[.020”] Jammy Dog tape as guides to align .75mm[.030”] Jammy Dog tape masks that make the stripes.  I removed the guide tapes in between the stripe masks prior to spraying Tamiya XF-6 Black overall, then removing the stripe masks to reveal the motif.  Not as crisp as a factory made model, but I am satisfied.



This model is for the cabinet collection, however I can easily advance the era at Fillmore from June of 1942 to June of 1944 to include them for operations.  I may do this from time to time for variety.