I have an extensive collection of Z-scale locomotives (some are older (15-20 years) Z-Scale Maerklin equipment). Can I convert the locos to Digitrax, or must I buy some other brand of loco to use Digitrax?
Maybe yes, maybe no. It depends upon the size of the locomotive and how much space is inside.
There are several Z-Scale layouts that use Digitrax decoders. Z scale railroaders are very persistent and precise so, they are often able to install decoders where members of other scales would fear to tread.
Digitrax continues to design smaller and smaller decoders aimed at the Z scale market. Z Scale manufacturers continue to work to make their designs more DCC friendly. It will be a case by case decision on whether a particular Z Scale loco can be fitted with a Digitrax decoder.
Digitrax has a long standing relationship with Micro-Trains and our DZ123MO is a drop in decoder installed in their GP-35. As other Z scale locomotives are released, watch for more releases of drop in decoders for Micro-Trains.
The smaller Maerklin locomotives, such as the 8800-type (Class 89 0-6-0), the 8864-type (V60 Class) and the 8895-type (2-6-0T engines) are too small for most current decoders. The Class 24 2-6-0 gets a "maybe" rating because it may be possible to install a decoder in the locomotive's tender. The larger steam engines also are "maybe's" for the same reason. The four axle diesels are functionally similar to the electric locomotive's mechanism. Maerklin mini-club motors have traditionally been 8 Volt DC motors, so you would need to adjust the output voltage of the decoder, probably adjusting CV05 to a much lower speed setting (thus a lower top voltage).