Class 70

Updated: August 2026 – Small, short, compact: the Class 70 ranks among the smallest standard-gauge steam locomotives in the Reichsbahn’s class scheme. Behind it stands the Bavarian Pt 2/3 class, a passenger tank locomotive with only two coupled axles. Its name alone explains almost the whole machine – once you know how to read it.

What is the Class 70?

The Class 70 is the Reichsbahn designation for small passenger tank locomotives of Bavarian origin, above all the Pt 2/3 class. These engines have the wheel arrangement 1’B: a leading carrying axle at the front, followed by two coupled driving axles. There is no separate tender; coal and water sit on the locomotive itself.

Locomotives like this were built for local and branch lines with light trains and limited route capacity. Large, heavy engines would have been neither economical nor permitted there. Today the Class 70 is a historic vehicle with no regular service; encounters happen exclusively in a museum setting, as maintained by the Bavarian Railway Museum in Nördlingen with its collection of Bavarian locomotives.

Learning to read the Bavarian class system

Before the Reichsbahn unified things, each state had its own designation system. The Bavarian one is especially easy to read, because it names the axles directly – as a fraction of powered to total axles.

Component	Meaning	Example
Capital letter	Purpose: P = passenger train, G = freight train, S = express train	S 3/6
Lower-case t	Tank locomotive rather than tender locomotive	Pt 2/3
Numerator	Number of powered axles	2 of 3
Denominator	Total number of axles	3 in total
Roman numeral	Design variant within the class	BB II

Once you’ve understood this logic, you can read Bavarian designations without looking anything up. The famous express locomotive Class 18.4–5 with the Bavarian S 3/6 is named accordingly: express locomotive, three of six axles powered. And the narrow-gauge Class 98.7 with the Bavarian BB II shows that special designs fitted into this system too.

How to identify a Class 70

The general sequence for identifying vehicles – from the rough body shape to the exact number – is described in the guide to identifying classes.

Classification within railway operations: the world of the local branch line

Small tank locomotives like the Pt 2/3 belonged to an operating environment that no longer exists: local and branch lines with few carriages, short runs and frequent changes of direction. There, what counted wasn’t power but economy and manoeuvrability. A locomotive that can run back without a turntable and copes with light axle loads was exactly the right answer.

For observation today that means: you’ll find such machines almost exclusively at heritage railways on former branch lines – exactly the setting they were built for. Photographically that’s a stroke of luck, because vehicle and surroundings match: a small station, semaphore signals, short trains.

Technically, the design results from two limits. First the axle load: branch lines had lighter track and weaker bridges, so heavy engines simply weren’t permitted there. Second the curve radii: branch lines often followed the terrain instead of a straight alignment, with tight curves that a long rigid wheelbase couldn’t have managed. A short locomotive with only two coupled axles solves both problems at once.

The price for this was low power. A Pt 2/3 hauled short trains of a few carriages, and no more was ever intended or possible. It’s precisely this ratio of small locomotive to short train that makes a heritage-railway photograph from this era feel right – a train that’s too long behind such a machine immediately looks wrong.

Photographically, such a small locomotive calls for different picture ideas than an express engine. Wide shots with landscape work better than tight frontal images, and the train often looks more coherent in a wide view than in close-up. The basics for that are covered in the guide how to photograph steam trains. For comparison with a considerably larger passenger tank locomotive, it’s worth looking at the Class 64.

Spotting: hunting down small steam locomotives

Because there are no diagrams, research replaces the timetable. Three sources get you there.

Heritage railways on branch lines. That’s exactly where small tank locomotives are used, because they suit the line and train length. Their seasonal timetables are fixed early and often even name the intended locomotive.

Societies and depots. They’re the first to report overhauls, boiler certificates and returns to service. A locomotive currently undergoing a general overhaul at the Meiningen Steam Locomotive Works won’t be seen during the current season – which saves you an unnecessary trip.

Event calendars and the community. Steam festivals, anniversaries and photo days bring several vehicles together in one place. How to find such dates systematically is shown in the guide to heritage railways and special trains. If you spot something yourself, the guide to reporting sightings helps make the information useful for others too.

Common mix-ups

Conclusion

The Class 70 is a vehicle that teaches two things at once: the Bavarian class system, which packs purpose and axle count into four characters, and the design of the small branch-line tank locomotive. You can recognise it by two coupled axles, one leading carrying axle and the absence of a tender. You’ll only encounter it in museums – most likely wherever a heritage railway operates a former branch line.