Comment by nic547

Assuming you have the yellowish, metal tracks (M-Track) it should work more or less.

Electrically the tracks with the connectors for power might have capacitors for radio interference reasons, they're unnecessary for and cause problems with the digital signals.

With regards to the wheel-track geometry, Märklin hasn't changed that much and most modern rolling stock compatible with the "Märklin system" (commonly referred to as "3L"/"AC") should work on M-track. Only the small "industrial radius" tracks might be a bit problematic in general and longer cars can hit turnout signals (mostly a problem with long passenger cars that aren't shortened to 1/100 or 1/93.5 scale). Some manufacturers have created "universal" wheelsets, those might be prone to derailments.

Digital trains need clean rails for proper operation, m-track is more vulnerable to rust and really needs proper rust removal, especially after not being used for a while.|

AFAIK it's not that rare to use m-track for storage yards and "non-visible" track rather than throwing it away.