The rise and fall of cabless locomotives, also called B-units, is a story tracing back to the beginning of dieselization. A cabless locomotive is simply a diesel locomotive without a cab for a crew to occupy. This differs from a slug, which has no prime mover and requires power from a mother unit to provide tractive effort to move a train.
EMD built hundreds of cabless units for both freight and passenger service, first building covered-wagon-type cabless units to mate with their cab-equipped E- and F units, which dominated the industry early on, then transitioning to cabless hood units when a handful of Class Is held onto the concept that not every locomotive needed a cab in freight service.
Union Pacific, who bought the most cabless hood units, ordered over 200 in the 1950s and 1960s in three different axle arrangements, four, six, and eight-axles from multiple builders. While the vast majority of cabless units over the decades were built by EMD and Alco, the latter primarily in the covered-wagon-era, Burlington Northern did order 120 cabless B30-7As from General Electric in the early 1980s. It also wasn’t uncommon for railroads to convert wreck-damaged units to a cabless locomotive during repairs.
Today, it’s difficult to find cabless units roaming the rails. Santa Fe owned a fleet of 23 GP60Bs before the merger, with a handful of those still in service today on BNSF, currently assigned to secondary service in the Pacific Northwest. BNSF also uses a few cabless SD40-2s from merger partner Burlington Northern on its hump in Galesburg, Illinois. Norfolk Southern still has a single Rail Power cabless RP14BD on its roster, but it’s currently stored. A few Class Is still roster older covered wagon cabless units, mainly for business train service or as power units for rotary snowplows on BNSF Railway and Union Pacific. Unfortunately, any cabless hood units that trickled down to short lines and regionals over the decades are no longer in service today.
With trains being run with fewer units positioning cabless units within a consist becomes more difficult.
I would have loved to read a little more about WHY they fell out of favor. Aside from the idea that they are less flexible as locomotives. Today that doesn’t really seem that important…compared to cost savings. Now, it seems we can expect ENGINEER-LESS locomotives, and even LOCOMOTIVE-LESS self powered railcars. These B units are seeming more relevant than they have for a while!
I’ve read it’s all about standardization. Easier to keep everything the same, even though it costs a tick more. I agree, B units should still be around.
Baldwin also offered B units to match with cab equipped units.