Marklin PO ('Paris-Orleans') gauge one CL 3021 electric locomotive for the French Market. This version was made 1914-15 between the earlier PO "tunnel motor" (similar to the UK market engine but with the green PO livery applied) and the later 64/13021 with the "steeplecab" appearance on two distinct bogies. This version used the newer "steeplecab" body in place of the low-roof tunnel motor body, but retained the tunnel motor's visible underframe along each side with two very simple bogies in between those frames. It also kept the older high voltage motor and large "knife switch" reverse unit within the cab, the reverse being operated by an exterior rod and handle. The body was hand painted (lots of rivets), and decorated with brass plates as well as a number of transfers simulating smaller signage. Following some work, this particular example is now running quite well on about 25-30 volts DC. It has replacement headlights and some other issues (including a missing piece on the underframe on one side) , but the paint and lettering have held up very nicely over the years.
Some further work on the locomotive. The reproduction headlights have been replaced with Marklin high-current switched headlights that look much better. This loco may have originally had an even earlier headlight type, but these are certainly better than the reproductions. The ones I installed are apparently from the 1924-26 period; on these instead of flipping the switch, you turn the insulator on top of the headlight and it moves up/down on the screw thread. Tightening it down presses the contact arm against the headlight case, completing the circuit. The standoff below the lamp is something I improvised to make it fit in the space. The Schiffmann Sammlerkatalog Band 2/B has an interesting page on these lights, see attached. Does anyone have a wiring diagram for these type of headlights?
I also replaced the modern electrical socket that a previous owner had installed on the end of the loco with an original Marklin switch.