Key takeaways
- The Class 66 is a tiny series: only two engines were built in 1955, 66 001 and 66 002.
- It was intended as successor to the Class 64, but arrived at a point when steam traction was already being phased out.
- Fastest way to identify one: a tender locomotive, three coupled axles, a two-axle trailing bogie at the rear – wheel arrangement 1'C2'.
- The number alone is enough: with only two engines built, every sighting can be identified without doubt.
- No regular service: the class exists solely as a preserved historic vehicle.
Contents
Fact file
| Vehicle type | Tender locomotive for passenger trains (new-build locomotive of DB) |
|---|---|
| Wheel arrangement | 1'C2' – one leading axle at the front, three coupled axles, two-axle trailing bogie at the rear |
| Year built | 1955 |
| Number built | 2 locomotives (66 001 and 66 002) |
| Intended role | Successor to the standard tender locomotive Class 64 in passenger service |
| Service status | No longer in regular service; preserved historic vehicle |
Identifying features
Is this really the class in front of you?
- Tender locomotive with no separate tender and welded, smooth-sided water tanks
- Wheel arrangement 1'C2': one leading axle at the front, three coupled axles, a two-axle trailing bogie at the rear
- Post-war styling: clean lines, few rivets, looking more modern than pre-war designs
- Asymmetric appearance – shorter at the front, longer at the rear than a 1'C1' engine
- Vehicle number 66 001 or 66 002 – there are no other engines
- Only found in museums, never in regular service in any form
Updated: August 2026 – Some classes comprise hundreds of engines. The Class 66 consists of exactly two: 66 001 and 66 002, built in 1955 as a new-build tender locomotive of the Deutsche Bundesbahn. It was intended as successor to the Class 64 – and arrived at a moment when steam traction was already being phased out. For spotters, it’s therefore one of the rarest encounters there is.
Spotted one of the two engines?
For a class this small, every single sighting counts – log it straight away with Traintrack.
What is the Class 66?
The Class 66 is a tender locomotive for passenger trains of the Deutsche Bundesbahn, of which only two examples were built in 1955. It carries wheel arrangement 1’C2’: a leading axle at the front, then three coupled driving axles, and a two-axle trailing bogie at the rear.
It was meant as a modern successor to the widely used Class 64 for passenger trains on branch and secondary lines. A full production run never happened: the Bundesbahn switched to diesel and electric traction during those same years, so a new steam locomotive class no longer made economic sense. Today the Class 66 is a purely historic vehicle.
What the number 66 means in the Reichsbahn scheme
The Bundesbahn also carried on the classification scheme of the Deutsche Reichsbahn. The first digit indicates what a steam locomotive was built for and whether it hauls a separate tender.
| Number range | Purpose | Type |
|---|---|---|
| 01–19 | Express train | Tender locomotive (with separate tender) |
| 20–39 | Passenger train | Tender locomotive (with separate tender) |
| 40–59 | Freight train | Tender locomotive (with separate tender) |
| 60–79 | Passenger train | Tank (tender) locomotive |
| 80–96 | Freight and shunting service | Tank (tender) locomotive |
| 97–99 | Rack, local and narrow-gauge locomotives | mixed |
The 66 falls within the passenger tank-locomotive range, right next to classes such as the 64 and the Class 65.10. Within this group the number roughly rises with size and axle count – the compact 64 sits below the heavier 65, and the 66 follows on as a late new design. The upper end of the same group is marked by the fast push-pull locomotive of the Class 78 with the Prussian T 18.
How to identify a Class 66
For a class with just two engines, the vehicle number is the fastest route. Still, it’s worth being able to read the body style – especially in older photos where the markings aren’t legible.
Rule out a separate tender
Water tanks along the sides of the boiler and a coal bunker behind the cab: that's a tank locomotive. A separate tender rules out the 66 immediately.
Count three coupled axles
Three equally sized wheels linked by coupling rods. Four or more point to heavier types such as the Class 65.10.
Look at the rear end
Two smaller axles in a shared trailing bogie at the rear – that's the difference from the symmetrical 1'C1' design of the Class 64.
Assess the surface
Smooth, welded components and few rivets point to a post-war build – a sign of a new-build locomotive.
The general approach to identification – first the vehicle type, then the body style, finally the number – is described in the guide to identifying locomotive classes.
For small series, always secure the number
When a class consists of only a handful of engines, an extra photo of the markings on the cab or buffer beam is worth more than another general view. It makes the sighting verifiable beyond doubt later on.
Context: what the Class 66 tells us about its era
The Class 66 is more interesting technically than operationally. It shows how, in the mid-1950s, the Bundesbahn tried once more to modernise steam locomotive construction – with welded assemblies, easier access for maintenance, and a wheel arrangement able to carry more supplies than the older 1’C1’ design.
At the same time, the shift in traction was already under way: electrification on the main network, diesel railcars and locomotives on secondary lines. New steam locomotives could no longer compete with the lower operating and staff costs of the new traction types. That’s why it stayed at two engines – a pattern repeated in several late steam locomotive projects.
This situation is no isolated case. Several late steam locomotive projects of both German railway administrations got stuck at prototype or very small series, because the circumstances shifted between design and delivery. What was conceived as a technical improvement arrived too late from a business standpoint. For anyone interested in technology, that’s exactly the appeal: these engines show how far steam locomotive design had still developed – and how little that changed the outcome.
For observation and photography, this means: you will never see the Class 66 in the operational role it was built for. What remains is its museum presentation – and the challenge of making an interesting picture of a vehicle that mostly stands still. How to frame steam locomotives well even without a run is covered in the guide how to photograph steam trains.
Keep an eye on rare vehicles
Community sightings show you where historic engines are currently being displayed or moved.
Spotting: how do you even find a tiny series
The smaller a class, the more the search shifts from observing to researching. With only two surviving numbers, the key question isn’t “when does it run” but “where is it right now”.
The starting point is railway museums and collections with a larger steam locomotive stock, such as the Süddeutsches Eisenbahnmuseum Heilbronn. Their vehicle lists usually also state whether a vehicle is on display, in storage or on loan. After that, it’s worth checking society announcements: overhauls, transfers and loans get communicated there earlier than anywhere else. An overview of the society scene and how it works is given in the article on railway societies in Germany, Austria and Switzerland.
The community also helps: when a rarely shown vehicle is moved or put on display again, that almost always shows up first in sighting reports and forums. To keep your own finds findable in the long run, it’s worth building a structured photo archive with clean naming by class and number.
Museum grounds are subject to house rules
Exhibition halls, engine sheds and open-air sites are operational or museum grounds. Barriers, designated paths and staff instructions are binding. Tracks and operational railway land are not to be entered – even when a vehicle merely "looks" parked.
Common mix-ups
It points to the Class 66 if …
- it's a tank locomotive with no separate tender
- you count three coupled axles
- a two-axle trailing bogie sits at the rear
- the number reads 66 001 or 66 002
Look more closely if …
- the vehicle is inside a shed and the running gear is hidden
- you only have a detail or front-on shot
- the markings are painted over or incomplete
It's not a 66 if …
- only a single leading axle sits at the rear – more likely Class 64
- you count four coupled axles – more likely Class 65.10
- a separate tender is attached
Verdict
The Class 66 is less a class than a full stop: two engines, one build year, one idea overtaken by technical change. You can recognise it by the combination of tank-locomotive body, three coupled axles and the two-axle trailing bogie at the rear. And because there are only two numbers, every documented sighting is automatically unambiguous – a good reason to record it especially carefully.
In short
Two engines, wheel arrangement 1'C2', built in 1955: that's the Class 66. A historic vehicle with no regular service, which you'll only find through museums, collections and society announcements.
Record rare encounters
Number, date, place and occasion in one app – so that even a one-off sighting stays verifiable for good.
Summary
- The Class 66 is one of the smallest German steam locomotive classes ever built: two engines, one year, one purpose.
- Its wheel arrangement 1'C2' sets it clearly apart from the symmetrical 1'C1' design of the Class 64.
- It stands as an example of the late new-build steam locomotives that were overtaken by the shift to diesel and electrification.
- Sightings are correspondingly rare and deserve especially careful documentation.
Frequently asked questions
What is the Class 66?
The Class 66 is a tender locomotive for passenger trains of the Deutsche Bundesbahn, of which only two engines were built in 1955: 66 001 and 66 002. It has wheel arrangement 1'C2' and was intended as successor to the standard Class 64. It is no longer in regular service today.
Why were only two locomotives built?
Because steam traction was already in retreat by the time it was developed. In the mid-1950s the Deutsche Bundesbahn was heavily committed to electrification and diesel traction. A new steam locomotive class would no longer have paid for itself – so the planned production run ended up as a pair of engines.
What does the wheel arrangement 1'C2' mean?
At the front runs a single leading axle, followed by three coupled driving axles, and at the rear a two-axle trailing bogie carries the end of the locomotive. This layout is deliberately asymmetric: the larger rear supply of coal and water needs more load-bearing capacity.
How do I tell the Class 66 apart from the Class 64?
By the rear end. Both are tender locomotives with three coupled axles, but the Class 64 has only a single leading axle at the rear (1'C1'), while the Class 66 has a two-axle trailing bogie (1'C2'). The styling also differs: the 66 looks smoother and more modern.
What are new-build locomotives?
Steam locomotives newly designed after 1945 – as distinct from the standard classes of the 1920s and 1930s and the older regional-railway designs. They relied on welded construction, simplified maintenance and modern boilers. Their production period stayed short because diesel and electric locomotives took over quickly.
Does the Class 66 still run today?
Not in scheduled service. The class is a historic vehicle with no regular service. If you encounter one, it will be in a museum setting – as an exhibit or at an event. Ask the relevant custodian about its current condition and location, as these can change.
How do I tell which of the two engines I'm looking at?
By the vehicle number. There are only 66 001 and 66 002 – so every sighting is unambiguous. Note the number together with date, place and occasion; for a class this small, practically every documented encounter is a special one.
Where do I look for opportunities to see it?
At railway museums, heritage railways and societies. Their vehicle lists and event announcements are the only reliable way to find out. The locations of historic vehicles change through loans and overhauls – so always check the current status rather than relying on older overviews.
Log your sighting of the DB Class 66
Date, location and vehicle number logged in seconds – and visible to the community.
Related classes
Class 64
The Class 64 is the Reichsbahn's standard tank engine for passenger trains: 520 machines, 1-3-1 wheel arrangement, nicknamed Bubikopf. Here's how to recognise it reliably.
Steam/specialClass 65.10
Class 65.10 is a heavy passenger tank locomotive from the Deutsche Reichsbahn's new-build programme. Here's how to recognise it and find it on heritage railways.
Steam/specialClass 78
The Class 78 is the Prussian T 18: a large passenger tank locomotive with wheel arrangement 2'C2' that could run at 100 km/h in either direction.
Steam/specialClass 95
The Class 95, the Mountain Queen, is one of the largest German tank locomotives: five coupled axles, two carrying axles, built for steep gradients.
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Steam/specialClass 98
The Class 98 groups together the branch-line locomotives of the state railways – light engines for lightly built secondary lines. Here's how to place them.
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