uhh its a similar but not the same class as the de2 from derail valley, and I mostly built it bc the 621 is my favorite switching loco outside of whitcombs.

It is currently set up as a dumby, but it should be increadibly easy to get it to run., will eventually fit it
btw thanks lebassin for the buffers and whatnot, they're great, check em out

also dammit im proud of this thing, i think this my first half decent lookin diesel

Oh! so I added a motor chassis in, what you do with that is you find a motor (About athearn gp whatever dimentions, so housing is 25mm L x 18mm W x 24mm H) glue it into the cradle on the chassis. Then you take a small rubber band (30mm in length or there abouts) and you stick it around the axle of the wheel and the shaft of the motor. At this point it is advisable to put some sort of hot glue glob on the end to keep the band from rolling off. Then you take a wire and wire it onto one side of the motor (and I recommend adding a resistor in line as well on one end) and wrapping the other end of the wire around the axle of the wheel. Repeat for both sides and whatnot and bam!

It is kinda experimental, I've only done a few prototypes, but if you want a cheap loco, uhhh go for it.
Don't do this if you want a proper loco tho, its mostly so a kid can use it or whatever and get involved in the hobby cheaply
half the reason I do this stuff lol