What is the unit that looks like an Engine, but no cab,just power?

Answer 1

Those could be a B-unit, calf, or slug.

Here's an A-unit and a B-unit:
http://www.pacific-western-rail.com/view_product.php?ProductID=43614

Here are some cow-calf pairs:
http://www.northeast.railfan.net/diesel133.html

Here's a slug
http://www.trilliumrailway.com/galview.asp?p_name=168.jpg&height=800

Now, B-units and calf locomotives are full locomotives but with no comfortable cab. They often have minimal "hostler's controls" so the locomotive can be moved by itself around the shop and yard.

A slug is simply traction motors and extra weight. For instance a regular locomotive might have a 1500 horsepower engine, but at very low speeds it can only apply a fraction of that power to the rails, before the wheels lose traction and spin. So the engine has extra power available. Enter the slug; more wheels, motors and weight to use that extra power.

Answer 2

They have several different names, depending on age and manufacturer, and what type you mean. The B units were really tall, like the main cab unit, just with no cab. But there were half-height units, some were called Cow and Calf units. Others were called slugs. Still others Mules, I think. The slugs or calves are much shorter units, about half as tall as a full-size engine, with no cab, just a low metal housing, meant to back up normal cab engine with extra power thru the MU connections.

Answer 3

It is a unit just for power. Years ago they called it the "B" unit and the "A" unit had the cab for the engineer. Diesel locomotives depending on the weight of the train and if there were hills to climb over could add or subtract power as needed by putting locomotives together or taking some away.

Answer 4

We usually called them slugs, havent seen many lately, the BNSF has a few ex Santa Fe units. I think they were a good idea, instead of having hundreds of barely acceptable cabs on their locomotives, they can have more B units and invest in more safer cabs with adequate sound insulation and seats that dont break down your back after 20 yrs.

Answer 5

These were called B units. They looked very much like E and F unit diesl locomotives, except there was no cab. The "B" stood for booster. As the name implies, the B units provided more power to pull heavier longer trains.

Answer 6

They are called B-units.

It was real popular back when the diesels first went into mainline service, with the EMD FT. The A-units are cab-equipped, and when needed, cabless B-unit locomotives are coupled behind it to give the train more power.

B-units reached its most extreme development with the EMD DD35B in the 1970s.. It's an 8-axle, 5000hp cabless diesel locomotive, most famous in Union Pacific service. (The cab-equipped version was the DD35A).

B-units are not as popular today though. Far as I know, all of the locomotives being built today by EMD and GE are all cab-equipped.

Hope this helps!

Answer 7

Indeed these are "B" units (where as cab units are considered "A" units). Along with their other names (such as cowl and boosters) there are also units known as slugs or road slugs, which are used for increase traction and are only a hood and cab with traction motors (where the diesel engine, prime mover, was once housed there is added weight for an increase in traction).

Answer 8

Yep. B units.

But, they weren't just for road service. EMD made switchers as B units, called 'cow and calf' units when MUed with the unit with the cab. I think they were designated as SW7, but I ain't sure on this point.

I liked having them when working in the hump yard. Switchmen didn't like to lace too many air hoses, so the extra two trucks of engine brakes came in handy.

There were others, called "booster" units, that were used in the yards at the rail yard in Colton, California. These may have been custom built by the SP, though. They had no prime mover (motor) in them, but were loaded up with concrete for weight and traction. The traction motors were supplied by electricity by the controlling unit's prime mover.

Answer 9

They are called drones or slugs.

Answer 10

It is an engine.