What are these cars for?

[Anonymous]

HI all,

As a newbie, I have a couple of questions about cars I have seen in the mail order catalogs. I hope that you can help.

1) What is a dynamometer car? What are they used for? Where would they be used?
2) What is a "Calf" engine? What are they used for? Where would they be used?

I would greatly appreciate any information

cmc

[Anonymous]

1) A dynamometer car is usually plugged-in right behind the locomotive/s. This car carries all sorts of electronic equipment, and is designed to give accurate measurements of the tractive effort and horsepower of the loco/s.

2) A "calf" is a locomotive without a control cab. Usually these are the smaller yard switchers, like SW9, SW1200, MP15. These switch engines were either ordered this way, or modified so there is no control cab. The controls are hooked up to the "cow", or identical unit with a cab. The engineer in the lead unit controls both with one set of controls. Most likely you will hear the terms together, like; "cow/calf" as you can't run the calf by itself.

[thirdrail1]

The "calf" locomotive was almost entirely an SW9 without a cab, but was not offered as such. EMD sold a locomotive known as a TR6 or TR9 which consisted of cow and calf units that were originally connected by a drawbar. These were sold to compete with the two prime mover center cab transfer (TR) units being offered by Baldwin and Lima. I don't think EMD ever offered the "calf" unit as a "sold alone" model. The models far outstripped the prototype in popularity.

[Anonymous]

Hi. The Dynameter car was designed to be pulled between the engine(s) and the rest of the train and though the equipment in side the dyno car could calculate the pulling power of the engine. The calf engine is nothing more than an engine built without a cab and was basically a cost cutting thing. They would need a mother engine, one with a cab to operate and were used like "B" units. Hope I Helped and I'm sure someone esle out there will have more details for you, but that is the basics of what they were. Jamie

[Anonymous]

CMC,

I'd just like to point out something since you asked about the "calf" locomotives. Eventually you will run across what is termed a "slug" locomotive. While the calf units were essentially "B unit" switchers, and could not be operated separately from the "cow" or "mother" locomotive, slugs are a similar breed. The difference between "slug" and "calf" is the presence of a power plant. A calf has its own power plant, or diesel engine, to generate electricity to turn the traction motors on each axle. A slug does not have a power plant and instead relies on a mother locomotive to provide electricity for it. The calf locomotives, to my knowledge, were built without cabs but the various slug units were custom built by the railroads. Probably the best way to spot the difference between the two is to look for exhaust stacks. If you see them, it's a powered unit. If you don't see them, chances are it's a slug.

RC

[Anonymous]

Thanks for all the great information. I am looking forward to learning more in the future.

CMC