Dual Cabs A/B units is there a difference.

[lwmlwm44]

I recently bought my first 2 engine diesel set marked as a A and B units.

I was going to mark them as to which one was the A and B unit on the engines somewhere but got them mixed up after removing them from the boxes they were in.

My question is and this may be a dumb one for which I have been known to ask some screwy questions is   Is there a difference between the 2 units.

Assume the A unit would be the lead engine and the B unit would following in reverse after it or does it really matter if perhaps the B unit was the lead engine.

Also.............when getting a and b units does the b unit usually have sound if the a unit has it.    Just curious

Larry

[Joe Satnik]

Dear Larry,

B units are cabless. 

Perhaps you mean powered/non-powered.

Powered units weigh about 5 times as much as non-powered.

If they are identical,  (both powered) use either one as the lead.

What make, model and item number is your set? What are the road numbers on the side of the cabs?

Hope this helps.

Sincerely,

Joe Satnik

[OkieRick]

What you have is probably two locomotives 'piggy-backed' or running 'front-to-rear.' I call them A/B units also no matter the shape of the 2nd unit.  Usually the lead or powered loco will be one number less than the rear un-powered loco.  A popular pair in train sets I see alot is the Santa Fe locos #1350 (lead) and 1351 (rear).

If you're fortunate enough to have sound the electronics and speaker may be housed the  in the rear locomotive. 

And...you may have two powered locomotives.  If they're DCC you'll have to set this up as a consist.


Rick

[pdlethbridge]

a typical A unit
a typical B unit
a typical A unit and B unit

[rustyrails]

Well, I had a perfect answer, but three pictures are worth all my words.  I will add that most B-units do have a control station at one end to enable a hostler to move the unit around a shop or yard.  Cabless "booster" locomotives ie: B-units resulted from railroad/union contractual disputes as to  what constituted a "locomotive."   In fact, the original road diesel locomotives, the EMD FT's, were coupled by drawbar (a semi-permanent coupling) so there could be no dubt that one FT-A and one FT-B were only ONE locomotive.
Rusty

[jward]

What you have is probably two locomotives 'piggy-backed' or running 'front-to-rear.' I call them A/B units also no matter the shape of the 2nd unit. 

Rick

to a railroader, the term b unit mean a complete locomotive, not equipped with a cab. the proper term for the following unit in a consist is "trailing unit".......oone can avoid much confusion by keeping this distinction.

training units can be pointed in either direction, a switch inside each unit tells it which direction to go in response to commands from the lead unit. which idrection it is pointed varies from railroad to railroad. some prefer the last trailing unit in consist to be pointed the opposite direction from the leader to minimize turning the consist at the end of the run. others, like amtrak, prefer to keep the trailers pointed in the same direction as the leader, so that they can add or subtract units from the consist as needed.

[RAM]

I don't know how many of EMD FT's, were coupled by drawbar (a semi-permanent coupling).  The Santa Fe told EMD that they wanted couplers and not the drawbar on the first order.

[lwmlwm44]

The Unit I have is a Athearn Genesis G22130 F-7A/F-7A Set as marked on thebox.
Minneapolis and St. Louis  The box they came in is marked G 22130 A and G 22130 B  The box for each engine is marked 250-A and 250-C   Both units are powered and they boy have sound.   Sorry about the misuse of the term Cab.

Larry

[lwmlwm44]

Trying to up load some pics  reject saying upload folder is full the pic iam
trying to post is under the max size and wonder can anyone help me in posting a photo
here

[Woody Elmore]

There were railroads who installed a cab at one end of a B unit so that the engines could be moved with the B unit first.

[RAM]

I may be wrong but some if not all B-units had controls so the engine could be move but not for operation.  I don't think any of them had horns or lights.

[rustyrails]

I apologize if this shows up twice.  I tried to submit a picture and things sort of went south.  Anyway, RAM, just to prove that anything is possible, I submit the following.  The Rock Island Railroad had a least two E-type (passenger) B-units that were assigned to the Rocky Mountain Rocket.  These units had cabs and could operate independantly.  In operation, a B-unit was coupled behind an A-unit and ran along normally until a certain point in the trip where the train was broken up at a junction.  The B-unit headed off up one side of the junction with its part of the train while the A-unit took the rest and headed off down the other leg of the junction.  Coming back the train was reassembled.  You can find pictures of the units here:  www.umcycling.com/ri1.htm

I don't know much about the Rock Island, but I hope that someone who does can fill in the details for us.

Rusty