Märklin H0 - Model train locomotive (1)

Nice set consisting of six Märklin locomotives in used condition. The function has been tested (see photos of the test track).
All locomotives run, but not perfectly.
Except for the locomotive of MEPPEN-HASELÜNNER EISENBAHN, all others stall or are very loud and have problems switching.
The locomotive of MEPPEN-HASELÜNNER EISENBAHN runs relatively well.
In one locomotive a coupling has presumably been modified (likely conductive, see pictures).
There are various signs of use.
Due to the listed defects, which themselves are not drastic, the locomotives are offered as hobbyist/scratch-builders items, as cleaning and a revision are necessary. With a little dedication you can still get quite a lot out of these locomotives.
See for yourself the quality from the numerous pictures.