Identifying Train Classes: How to Recognise Any Locomotive or Multiple Unit

Updated: August 2026 – Identifying train classes sounds like rote memorisation, but it’s really a system: if you know which order to check which features in, you can place any vehicle within seconds – even one you’ve never seen before. This guide doesn’t give you a catalogue, but an identification key that works equally well for locomotives, multiple units and special vehicles.

Identifying a class: the short answer

You identify a class in four steps: first establish the drive type (electric or combustion engine), then the vehicle type (individual locomotive or fixed multiple-unit formation), then the axle count and body shape, and finally the number series on the vehicle. The first two steps split the entire German rolling-stock field into four large groups; the last two steps take you from there to the specific class.

The number series is the proof here, not the starting point: classes beginning with 1 are electric locomotives, with 2 diesel locomotives, with 4 electric multiple units, and with 6 diesel railcars. The guide on decoding train numbers for ICE, IC, RE and RB explains how the same numerical-logic idea works for train numbers.

Steps 1 and 2: Drive and vehicle type

These two questions do most of the work. They can be answered from any distance and each rule out half of all the possibilities.

Electric or combustion engine?

Look at the roof. A pantograph means electric drive. Exhaust and radiator openings, a visible exhaust plume when starting off, and a clearly audible engine mean combustion drive. A good extra clue is the line itself: without overhead wire, no electrically driven vehicle can run there in regular service.

Locomotive or multiple unit?

A locomotive is a self-contained vehicle that pulls or pushes coaches. A multiple unit is a permanently coupled formation in which the drive is distributed across several vehicle sections and which is described as a single unit. That’s more than a formality: with multiple units you identify a train set, with locomotives an individual vehicle – and both are logged differently in sightings.

The interactive identification tool

Answer four questions about the vehicle in front of you. At the end you’ll get the vehicle group, plus a pointer to where to search further.

Step 3: Axle count and body shape

Once the group is settled, you narrow it down within the group. Two features are almost always enough. It also helps to think in terms of manufacturer families: once you’ve internalised Alstom’s design language, you place related types much faster.

• Axle count. Count the wheels on one side of the vehicle and don’t double it – count axles, not wheels. Four axles are standard for passenger and modern general-purpose locomotives; six axles point to heavier designs.
• Bogies. Two two-axle bogies mean four axles; two three-axle bogies mean six. On multiple units, bogies often sit between the coach sections – that’s a recognition feature too.
• Front shape. Wedge-shaped, angular, rounded or aerodynamically shaped: for most classes, the front is the single most striking feature.
• Body construction. A continuous body, a centre cab, or separate bonnets – above all a reliable clue for shunting and older locomotives.

You’ll find concrete examples of this in the vehicle profiles: the profile of the Class 101 as a classic IC locomotive shows how strongly a front shape defines a vehicle, and the guide on recognising older diesel locomotives like the 218 and the “Ludmilla” explains why axle count is the most important distinguishing feature for diesel locomotives.

Step 4: The number as proof

Every identification ends at the running number. It’s shown on the side of the vehicle, and on multiple units usually near the doors on the coach body. Modern vehicles carry a twelve-digit number under the European scheme, which, alongside country and keeper details, also encodes the class block and the individual sequence number. The keeper here is not necessarily the operator: a vehicle can be in service for a group such as Abellio and still belong to a leasing company.

Number series	Vehicle type	Typical feature	Where you’ll see it
starts with 1	Electric locomotive	Pantograph, short body	long-distance, freight, regional service
starts with 2	Diesel locomotive	Exhaust, radiator grilles, engine noise	non-electrified lines, shunting duty
starts with 4	Electric multiple unit	Fixed formation under contact wire	S-Bahn, regional service, long-distance service
starts with 6	Diesel railcar	Fixed formation without contact wire	regional lines without overhead line
starts with 7	Engineering and service vehicles	Special equipment, work gear	worksites, maintenance
starts with 8	Driving trailer	Driving cab but no drive	at the end of push-pull trains

Practising identification

A station where long-distance, regional and freight traffic run closely alongside one another suits practice well – Hamm (Westf) main station delivers more types in two hours than most big-city hubs. If you’re just starting out, the tips for new trainspotters give you the right foundation, and for multiple units in long-distance service the ICE guide with sightings, photo spots and classes is worth reading.

Special cases: where the key reaches its limits

No identification key is watertight. Four situations come up regularly in everyday spotting and can’t be resolved with the four basic steps alone.

• Converted classes. Vehicles that have subsequently received a new engine or a different type approval look unchanged but run under a different class number. Here only reading the number helps – the type approval behind such conversions is often handled by engineering firms such as AEbt Angewandte Eisenbahntechnik.
• Dual-mode and hybrid vehicles. They carry a pantograph and a combustion engine at the same time. The question “electric or diesel” then simply has no clear-cut answer any more.
• Foreign vehicles. Locomotives of other railways follow their own numbering system. The body-shape features still work, but the number-series step doesn’t. At a border station like Basel SBB, vehicles regularly stand that can only be classified by body shape.
• Historic vehicles. Museum and heritage-society locomotives often carry old numbering schemes from earlier eras. The context for this is covered in the Drehscheibe Online guide to heritage railways.

In all four cases the same rule applies: identify as far as possible via body shape, note down the number you’ve read, and mark the sighting as uncertain rather than guessing. An honestly flagged uncertainty is far more valuable to the community than a confident but wrong identification.

Common mistakes when identifying

• Going by livery. Advertising locomotives and private-operator colours reliably lead you astray – the Drehscheibe Online guide to advertising locomotives shows just how much.
• Counting wheels instead of axles. A common beginner’s mistake that turns every four-axle locomotive into an eight-axle one.
• Mistaking a driving trailer for a locomotive. A driving trailer has a driving cab but no drive of its own – and its own numbering system.
• Counting multiple-unit sections individually. A fixed formation is one unit, not a collection of coaches. Logging each coach section separately skews your statistics.
• Only photographing the front. Without a side shot the number is missing, and without the number the identification stays a guess.
• Not documenting sightings. Only logging it turns recognition into a result – the overview of live sightings and real-time news shows how the scene handles this.

Conclusion

Identifying train classes is a skill, not a feat of memory. Drive type, vehicle type, axle count, number – this path works for every vehicle, even one you’re seeing for the first time. Lists and vehicle profiles are then only deepening, not a prerequisite. And because the number always has the final say, a side shot belongs in every serious sighting. Apply the key consistently for a week and you’ll recognise the vehicles in your region in passing after that. For the location work to go with it, the guide to railway photography with tips and locations helps, and for choosing a place to practise, the overview of the best stations for trainspotting in Germany.