I know the meaning of some of them, like GP stands for Bo-Bo wheels, and SD for Co-Co wheels, and T stands for tunnel motor, MAC stands for AC etc.
But there are lots of letters that I don’t know what they mean.
For example, SD40E what does E mean, and is 40 just a number of the series or does it mean something? Or for example in sd70M, what does M mean?
Or another thing that I don’t know is what does “-2” or “-3” mean. I assume its revisions on the model, but I’d sleep better if someone gave me a full list of meanings.
So can anyone tell me what ALL the letters and numbers mean?
M = wide cab or safety cab (SD70M)
B= cabless unit (GP60B)
E= in BNSF terms is remanaufactured by EMD or enchanced
F = B-B cab unit or cowl body
"E"8 = A1A-A1A cab unit
FP= B-B cab with passenger capablities
H = Head End Power
AC = either Alternator (GP38AC) or alternating currect (SD70MAC)
SW = swicher
MP = multipurpose switcher
X = experimental (GP40X)
Usually the numbers go with series.
40 series is like the GP 40 and SD40 and Dash 2 conterparts
45 is SD45 and such and so on and so on.
-2 and -3 refer to the technology under the hood
Well, the E probably designates that the unit was re-built, mabee by EMD. BN rebuilt many units to GP39-2 standards and several companys did the re-builds. They added the letter V to the VMV rebuilds, GP39V. M for the Morrison Knudsen rebuilds and E for the EMD rebuilds. So they are not really EMD nomenclature rather BN’s. The same goes for many SP rebuilds.
The -2 series designates a change in electrical gear to a modular setup in the cabinet where troubleshooting and repair became much easier.
I don’t think -3 is a EMD designation. It’s more like a designation the RRs use to distinguish rebuilds that have advanced electronics.
the number series kind of arbitrary. For a while it was like GE’s in that it would be about what the HP was in hundreds. But when the 30’s came out they did not want to have a lower number then GE so they claimed the 30 represented the fact that there were 30 improvements over previous models. From there they basicaly added 10 to each number series, 40,50,60,70. And then there were counterparts that had less horsepower either by not having a turbo (GP39-2) or haveing a smaller 12 cyl prime mover (GP38-2).
The AC designation on earlier units means that they had a alternator(AC) and rectifier instead of a DC generator hooked to the prime mover. On newer units the AC means that the traction motors are AC and have inverters to supply the motors with the proper AC frequency and amplitude from the DC coming out of the rectifier.
Then there are a few oddball designations like B for cabless,T for tunnel motor and F meaning full bodies (Cowl units). P means it is a passenger unit. Then there is H meaning the unit can provide HEP(Head End Power ) for passenger equiptment. And now we have e which means its a tier 2 emmisions compliant unit.
Some of the numbers are not even in the EMD catalog (historically speaking). IIRC, the GP-10 was an IC designation for rebuilt GP-9’s. I think I’ve heard of -18’s and -19’s in the same way, although I don’t recall the railroad(s). Some railroads use a type designation that resembles the manufacturers model number, some use something completely different (kind of like steam locos. How many names can you come up with for the 4-8-4? That’s a rhetorical question - keep the answer to yourself.)
For those among us who want to quantify what we spot, it can get frustrating. When you start adding “Phases” - a railfan term for the most part - you can get really confused. Was the water sight glass on the sixth door, or the seventh?
On rebuilt EMD locomotive an E at the end of the model number on the front of the frame indicates it was rebuilt by EMD, and an M indicated it was rebuilt by Morrison Knudsen of Boise, ID, and a V indicates it was rebuilt by VMV of Paducah, KY (formerly the I.C. shops there). Hope this helps a bit.
In response to an above question, the “R” usually means "Rebuild.
“M” doesn’t necessarily mean a wide cab, rather “Modified.” The M usually means the cab is modified, however in SP’s case, for example, the SD40M-2s were modified SD45 and SD40 carbodies meant to house the 645 engine.
“W” on the other hand, always means “Wide Cab,” but it’s on Canadian engines only.
In days of yore,a lower case “m” usually meant using much of the old stuff in a new carbody.Don’t know if it stood for modified,but the units were usually not rated with the horsepower of a new unit.For example,B&O traded in their EA cab and boosters and got back E8m’s,which were rated at 2000 hp rather than 2250 hp.
Here are 3 others
A as in SD40A an SD40 custom built by EMD for Illinois Central with a stretched frame for a larger fuel tank.
and P as in SDP35, SDP40, SDP45. Passenger versions of the common SD35, etc, who also had extended frames to allow room for a steam generator. or in the case of Erie Lackawanna, larger fuel tanks.
L as in SDL39 a custom built A1A A1A lightweight roadswitcher purchased by the Milwaukee Road for use on branchlines with bad track. Went to Wisconsin Central, now in Chile.
-3 generally refers to a computer controlled electrical and adhesion system, compaired to modular electrical systems used on -2s
And sometimes there is an A to designate that it IS cab unit. (DDA40X)
Here are a couple more I forgot:
X means that it’s an experimental unit.
I meand that the cab is isolated from the frame. The cab is mounted with rubber to better insulate noise from the cab
The -18 series was an EMD model, there were GP18s and SD18s built, these were the non-turbocharged counterparts to the GP20 and SD24. In turn the -18s were superceded by the -28 series which were in the EMD catalog for only a year and a half before the -38s came out only 14 GP28s were built for US railroads plus 10 in Mexico. Only 6 SD28s were built. The -18 series were built in larger numbers with the Missouri Pacific and Norfolk & Western having good size fleets of the GP18.
Well, the E probably designates that the unit was re-built, mabee by EMD. BN rebuilt many units to GP39-2 standards and several companys did the re-builds. They added the letter V to the VMV rebuilds, GP39V. M for the Morrison Knudsen rebuilds and E for the EMD rebuilds. So they are not really EMD nomenclature rather BN’s. The same goes for many SP rebuilds.
The -2 series designates a change in electrical gear to a modular setup in the cabinet where troubleshooting and repair became much easier.
I don’t think -3 is a EMD designation. It’s more like a designation the RRs use to distinguish rebuilds that have advanced electronics.
the number series kind of arbitrary. For a while it was like GE’s in that it would be about what the HP was in hundreds. But when the 30’s came out they did not want to have a lower number then GE so they claimed the 30 represented the fact that there were 30 improvements over previous models. From there they basicaly added 10 to each number series, 40,50,60,70. And then there were counterparts that had less horsepower either by not having a turbo (GP39-2) or haveing a smaller 12 cyl prime mover (GP38-2).
The AC designation on earlier units means that they had a alternator(AC) and rectifier instead of a DC generator hooked to the prime mover. On newer units the AC means that the traction motors are AC and have inverters to supply the motors with the proper AC frequency and amplitude from the DC coming out of the rectifier.
Then there are a few oddball designations like B for cabless,T for tunnel motor and F meaning full bodies (Cowl units). P means it is a passenger unit. Then there is H meaning the unit can provide HEP(Head End Power ) for passenger equiptment. And now we have e which means its a t