MaK DE 501 / MaK DE 502

Updated: August 2026 – Small shunting locomotives are the vehicles most identification attempts fail on: no large class number on the front, no well-known livery, often no entry in the usual lists. With MaK DE 501 and DE 502, the reliable path runs via a palm-sized metal plate on the frame – the builder’s plate. This page shows how to find it, read it, and interpret it correctly.

What are MaK DE 501 and MaK DE 502?

MaK DE 501 and MaK DE 502 are type designations for small diesel-electric shunting locomotives from Maschinenbau Kiel’s programme. The prefix “DE” stands for diesel-electric power transmission, the number places the machines in a power class, and the final digit separates two production variants within that class. Kiel’s type programme was later carried on by Vossloh, which is why closely related machines carry different builder’s plates depending on their year of construction.

Both designations are manufacturer designations, not class numbers. They therefore don’t appear in large digits on the vehicle, but in documents and on the builder’s plate. Anyone wanting to identify such a locomotive has to go via the manufacturer – just as with the older Kiel types of the MaK 240 B and 240 C series. The same logic applies at the heavy end of the programme to the considerably larger MaK DE 1002: same prefix, different power class.

The builder’s plate: the most important source of information on the vehicle

A builder’s plate isn’t a decorative item, but the vehicle’s identity card. It names the manufacturer, a running builder’s number and usually the year built. This information doesn’t change – unlike fleet number, markings and colour.

How to keep such detail shots findable for good is described in the guide to building a photo archive for spotters. Which metadata comes along automatically and how to use it is covered in the article on using EXIF data while spotting.

What the builder’s plate doesn’t do

Valuable as it is, the plate doesn’t answer every question. The following overview shows which source is responsible for what.

Question	Builder’s plate	Vehicle number	Observation of the vehicle
Who built the locomotive?	yes	no	no
Which specific machine is it?	yes, via the builder’s number	yes, via the running number	no
Who is the current keeper?	no	yes, via the keeper marking	partly, via markings
How many axles does it have?	no	no	yes, by counting
Is it approved for public tracks?	no	yes, through registration	no

The twelve-digit number itself follows a fixed structure: type code, country code, type block, running number with check digit, and keeper marking. The type code 98 marks diesel shunting and light locomotives, while 92 stands for diesel main-line locomotives. The full system is explained in the guide to reading the UIC number and its check digit.

Why so little is published about such types

For well-known main-line locomotives, you’ll find quantities built, years and power figures in every overview. It’s different for small works locomotives – and there are understandable reasons for that.

These vehicles were delivered in small batches or as one-offs, often to an individual industrial customer’s requirements. They spent decades on non-public tracks, where neither timetables nor diagrams are made public. Conversions, new engines, altered cabs and adaptations to the particular operation are the rule, not the exception. And because many machines changed owner several times, conflicting figures built up across different sources over the years.

For you as an observer, a clear conclusion follows: rely on what’s written on the vehicle. Builder’s number, vehicle number, markings and an actually counted axle number are verifiable. Everything else – supposed power figures from forums, guessed years of construction, secondhand quantities – doesn’t belong in a sighting note. A short, correct note is worth more than a long one that’s half-guessed.

That’s exactly why the specification panel on this page is deliberately kept brief for this group of vehicles. What’s confirmed is stated; what isn’t confirmed is left out – and that’s the more honest approach.

Where such locomotives can actually be seen

Small shunting locomotives work where wagons are delivered and collected: at industrial sidings, in ports, on works sites and at the edges of larger railway installations. Their duties are short, irregular and rarely announced publicly.

Anyone wanting to specifically observe shunting operations will find location criteria and approach in the guide to spotting at marshalling yards.

Common mix-ups

For the methodical approach to unfamiliar vehicles – vehicle type first, then body shape, then number – the guide to identifying classes is worthwhile. For comparison within Kiel’s programme, the page on the three-axle MaK 450 C also helps.

Conclusion

With MaK DE 501 and DE 502, what applies to almost all small works locomotives applies here too: the type designation supplies the structure, the builder’s plate the identity, and the vehicle number the official proof. Invented power figures help no one – a sharp photo of the plate, on the other hand, helps a great deal.