These little machines are Field Pushers and Pig Pushers. Operated by longshoremen, they move on a narrow gauge track adjacent to the rail yard tracks. These machines are used to move loaded coal cars , two at a time, from the "buck yard" to the barney pit where the cars are then pushed up an incline to the rotary car dumper.
The worst of railroad design. Please, send me your entries / suggestions for the "Album of the ugly trains of the world" (past or present, paint scheme or shape).