BEAUSABREHere's a three unit consist with A units #51 and #56 and an unidentified B unit.
I think Jersey Central was unique. Its A units bore numbers and B units had letters assigned but not displayed. Here's a three unit consist with A units #51 and #56 and an unidentified B unit.
https://www.railpictures.net/viewphoto.php?id=275549
and an EMD ad of #50, #A and #51 on the Newark Bay lift bridge.
https://ogrforum.ogaugerr.com/topic/nsou-heritage-cnj-1071---new-photo?nc=1
doublereefedIn the early days when they were all the same number, were the A,B,C,D appended to the number painted on the loco? As in 8223A, 8223B
That's the way most railroads did it, yes. It would be part of the ID number, it wouldn't be a separate letter stuck somewhere.
DSchmitt points out in his post above that SP began to remove the letter designation in 1949, so the SP F-units that had the letters in their ID would only have them for a brief period, 1-2 years or less.
... Googling images like crazy but can't figure out where the A,B,C,D would be indicated on a a F3A and F3B SP set like this, that were part of an ABBA set. Is it a letter on the rear, or?
With regard to numbering. In the early days when they were all the same number, were the A,B,C,D appended to the number painted on the loco? As in 8223A, 8223B... or just 8223 on everything? (I chose that number off of a photo of a model, so I have no idea if 8223 was ever in an ABBA under the same number.)
The F2 was the successor to the FT. It was 1350 hp the same as each unit of the FT A+B. Few railroads bought F2.
There were 74 A units and only 30 B units made and some railroads bought only A units.
A F2 A was often coupled to FT A+B to create an A+B+A set or a B unit coupled to a FT to create a A+B+B set.
https://en.wikipedia.org/wiki/EMD_F2
I tried to sell my two cents worth, but no one would give me a plug nickel for it.
I don't have a leg to stand on.
This is just a general F-unit comment, not specifically about SP.
EMD's FTs were designed to be used with an A unit and B unit connected with a drawbar, so you could run one A-B set on a train, or two sets together A-B+B-A (with "+" indicated they were coupled with regular couplers.) Many railroads bought and ran later F-units the same way - an A and B unit drawbar connected. Even if they created a four-unit set where all 4 units had the same number, they generally were still two A-B sets coupled together back to back. Part of the reason was many railroads in the 1940's still used roundhouses to service their engines - they hadn't yet built diesel-specific engine houses - and you could fit an A-B set of Fs onto a turntable to move it into a roundhouse stall.
In time, most railroads found it more convenient to fit all A and B units with couplers and give them separate numbers, so they could be mixed together as needed. A typical c.1950 mainline freight train needed around 4000 Horse Power, so two 1500-HP diesels (like an A-B set of Fs) were not enough, four units (A-B+B-A) was too much, but three (A+B+A) was "just right".
To add a little to what DSchmitt has said: it is not necessarily true that the decision in December '49 means that the locomotives were being mixed up in groups of less than four -- it may only mean that it was inconvenient to have to hold the other units out when one 'alpha' was being serviced, or take pains to get the serviced unit swapped out for a 'loaner' temporarily filling in on a four-unit 'locomotive'. But I'd be willing to bet there were longer or shorter consists of 'units' by that time, and once the union rules about firemen on additional MUed units was settled, there was certainly little if any reason to preserve the 'alpha' pretense that the four-unit consists were single articulated locomotives.
In the absence of more definitive history, look at photographic evidence to see if, perhaps increasingly at some point after 1947, there are 'other than four' locomotives in particular F-unit consists.
http://espee.railfan.net/spf03ab.html
"SP proper received its first 'covered wagons' in May of 1947, (SSW got FT's earlier). Placed in Classes DEF-1 and DEF-2, (later DF-1 and DF-2) deliveries continued until February of 1949 when superseded by EMD's F7 model.
All were delivered in 4 unit ABBA sets painted in Black Widow paint.
Southern Pacific originally numbered F units in sets of four, with one number and an alpha suffix. F A or cab units were suffixed A and D, F B units or boosters were suffixed B and C.
Due to locomotive shortages on the Atlantic Lines (Texas and New Orleans) starting in 1949, all F3 units were sent to the Texas and New Orleans, except #6138, 6139 and #8038, 8039
In December of 1949 SP decided the alpha suffixes had to go, and so a general renumbering of all system F units took place. The F A or cab units were given 61** numbers and the F B units or boosters were placed in the 8*** series.
Some of these F3's came back to SP and returned to original numbers, and some were rebuilt as F9m's"
doublereefedWondering how common SP Black Widow ABA freight consists were.
I don't know if you have looked here but there may be some helpful info if you dig for it:
http://modelingthesp.blogspot.com/2014/02/southern-pacific-f-unit-diesels.html
Good Luck, Ed
Wondering how common SP Black Widow ABA freight consists were. Seeing occassional ABA photos, although ABBA seems far more common. Any advice you can give me?
Thanks!