Calves as B units?

Model Railroader Prototype information for the modeler
1

I have seen straight switcher units cut into loco consists and it has just occured to me to wonder if any calf units were ever run on their own or with their cow cut into consists out on main track?

They are, after all, just a variety of B unit… aren’t they?

Thanks

[8D]

2

Cow-calfs used a drawbar, so “uncoupling” them for other use would be tedious.

Ed

3

Oh, and by the way:

I’ve got an attractive Athearn Southern cow and calf set that I decided to connect with a drawbar. Since the units are permanently coupled, I also decided to add jumpers between the units: 16 wheel pickup! NEVER a stall!

Ed

4

Dave,

Most ‘Cow & Calf’ units were delivered as a draw bar connected ‘set’. Many railroads did break up the sets and put couplers /additional MU hoses on their one-time transfer sets and could use the units in a consist. The MILW and CNW come to mind. Using them as ‘road power’ has several other issues though:

  • Gearing - many times they are geared lower. This will lower the maximum speed and could lead to ‘bird nesting’ of the traction motors if they are dragged faster by a road consist. Many times moving switchers even dead in tow will result in a 45 mph speed restriction for a train.
  • Air Brake Schedule - many times they do not have 24RL or 26L brake schedules.
  • Trucks - Most have AAR switcher trucks which are not double equalized, and ride rather rough at road speed.

So, in theory, they can be made to ‘MU’ with other road engines, but they may cause limitations to the consist they are used in.

Jim

5

To Jim’s list add non-alignment control drawbars which restricts the amount of tonnage that can be hauled behind the engine.

6

While both CNR and CPR had a limited number of switchers equipped with MU, the system used was not compatible with that of the road power. I believe they had a much simpler arrangement. Both roads also had light branchline road engines based on the switchers but with road trucks, namely the SW1200RS and the RS-23. These did have the full MU.

Mostly if you saw a switcher in a consist it was being deadheaded somewhere. They would be behind the operating locomotives because of the MU issue. The issue of alignment control drawbars seems to have become more of a concern in more modern eras, likely due to the much heavier tonnages now typical. Marshalling instructions would probably bury the dead switcher well back in the train.

John

7

As I recall, SP retrofitted their calves with couplers for greater flexibility, but never did I observe one mixed with road power under load. SP had such faith in these tiny titans that they were selected for inclusion in the GRIP rebuild program of the mid 70’s, but for a variety of reasons the program was cancelled before any work was perfomed.

Dave

8

On the CP I notice switchers cut into the power consist in between the road units. The non-alignment couplers won’t get into too much trouble that way. The switchers might swing over, but the road units won’t. Other places have a limit of 2 non-alignment units in a consist. Each railroad does things differently, depending on problems encountered in the past.

The power is usually kept all together at the head end. Deadheading units will have the MU air hoses hooked up (if available), as when they set up they set up hard, and could cause jackknifing problems.

9

The switchers in Canada that CP still uses (SW1200RS) are set up with the full MU capability, so they are indeed cut in between the road units. But if you do that with an old Alco S-4 or EMD SW900, with no MU ability, the only way it will work is if you use DPU technology to control the unit behind. The aged GP9s now used as yard engines retain the MU from their previous career. Second generation switchers like the SW1500 probably also have full MU.

John

10

The NYC was not above using a GP7/SW7 consist on local freights.

The B&O also changed the drawbar to couplers on their TR3 and TR4 sets.

11

Slightly OT but sometimes you see photos of a calf cow calf set.

I can recall seeing end cab switchers in freight consists on the C&NW – presumably at speeds that would not damage the traction motors, since they seemed to be under power and contributing to the tractive effort. I do not recall seeing a calf used in this way. I am pretty sure the CNW calf units had couplers. I’ll have to check the photos I took of the Butler yard deadline (former Chicago Great Western cow/calf combos, if memory serves).

I once asked a trainman why a local “turn” used Geeps when an SW switcher would have been more than enough power for the train. He responded that while they might need the higher speed of the Geep to get out of the way of the CNW’s remaining passenger service the primary reason was the SWs had no toilet. Makes sense!

Dave Nelson

12

[tup] [tup] [tup] Thankyou everybody. [:)] Some great stuff here. [:)]

Would someone explain the non-aligned control bars to me please?

Thanks

[8D]

13

Here’s one of the TH&B’s SW9s in mainline service, although it’s acting as a helper to get the Buffalo NY-bound train out of Hamilton, Ontario and up the Niagara Escarpment. Not equipped for mu, this is a doubleheader. At the summit, she’ll cut off and return light to Hamilton.

Wayne

14

AS far as switchers in freight consists; i remember that when BN still used end-cab switchers in Fremont and Omaha, they would appear behind the road power on local freights to and from the diesel shop at Lincoln, NE. I rather doubt they were used for tractive effort and were probably just “along for the ride”.

Another way to use a “cow and calf” in freight service - when UP originally bought their TR5 sets (SW9 cow and calf) they were used as Cajon Pass pushers. That provided a 2400hp “engine” that worked for the low speed pusher service. They didn’t last terribly long in that service, but they certainly were used there.

The semi-permanent nature of the “cow-and-calf” made them a lot less flexible than a pair of regular locomtives. A failure in one unit basically put both out of service until repaired.

Another appearance of switchers on freight trains; as the Union Pacific retired their fleet of 2-8-0s that had powered the Nebraska and Kansas branchlines many trains were run with Alco or EMD end-cab switchers well into the 1960s. So switchers don’t always have to stay inside yard limits.

15

This engine had non-alignment couplers. Tabs have been added to limit the swing of the coupler. Most engines have other limiting devices built into the draft gear.

!(http://i184.photobucket.com/albums/x218/MFJ_album/WSOR engines/WSOR 702/5-4-07071.jpg)

Here is a non-alignment coupler. Notice the lack of anything to interfere in the swing. Good for switching and getting into tight industry tracks, but can cause jackknifing under high buff loads.

!(http://i184.photobucket.com/albums/x218/MFJ_album/WSOR engines/WSOR 1504/5-21-08009.jpg)

16

These days they pretty much do stay in the yard, as they lack toilet facilities. MP15ACs do have a toilet available, so they can be used for road power.

17

Thanks, Mike.

Very clearly stated and illustrated.

“I did not know that.”

Ed