These wagons are very pretty, finely engraved, as always at REE, and not too fragile, unlike ANF tanks of the brand. Only buffers tend to escape.
The only complaint I have is the illumination of the tail lamps, whose power supply is random (and incidentally, the lantern appearance is not of IVa era).
On closer inspection, the tiny lantern supply printed circuit is not as simple as I had imagined at the beginning: indeed, it provides a constant — and realistic — lighting from about 4 volts, up to at least 16 V (I didn’t test beyond this value). What I thought was a diode (among others) is therefore probably a voltage regulator.
This circuit, held by two tiny plastic clips and an also tiny screw, is connected to the rear bogie by two black wires soldered to the middle of the current pickup strips, which rub against the inner side of the wheels.