Class 97

Updated: August 2026 – The Class 97 is the special case in the German steam locomotive numbering system: while almost every other number is sorted by purpose and wheel arrangement, this one number stands for a drive principle. Rack locomotives run where adhesion alone is no longer enough. This page explains how that works technically, what systems exist, and where you can still experience rack operation today.

What is the Class 97?

The Class 97 is the number group that the Deutsche Reichsbahn-Gesellschaft assigned exclusively to rack locomotives. That makes it an exception within the numbering system: bands 01 to 96 are sorted by purpose and type, while 97 is instead sorted by an engineering principle. The 98 was then reserved for branch-line locomotives and the 99 for narrow-gauge engines – both special categories too.

Rack locomotives are vehicles for route sections whose gradient lies beyond what can be safely managed with pure adhesion drive. In addition to the normal running gear they carry a driven pinion that engages a rack running down the centre of the track. This allows power to be transmitted positively – and, just as importantly, allows safe braking on the way down.

On the German state railway network, the rack sections have long since become history. Vehicles of this class are today historic objects; you experience rack operation in Germany mainly at tourist mountain railways with their own fleets. One of them is the Drachenfelsbahn, which has climbed from Königswinter up the Drachenfels since 1883 – metre gauge, with a rack, and running all year round.

How rack operation works

The core is quickly explained; the consequences aren’t.

Where the gradient still lies within the manageable range, pure adhesion is enough on its own – though that then needs a very powerful engine with steep-gradient equipment, such as the Class 95.

Rack systems compared

Not every rack is built the same way. The systems differ in construction, smoothness of running, maintenance effort and the gradient they can handle.

System	Rack construction	Characteristics
Riggenbach	Ladder rack made of rungs between two profiles	oldest widely used system, robust, comparatively noisy in operation
Abt	One to three flat-steel strips, teeth staggered	staggered teeth give a smoother ride, widely used
Strub	Solid profile with milled-in teeth	simple maintenance, head usable as a clamping surface for brakes
Locher	Teeth engaged horizontally on both sides	for extreme gradients, additionally secures against climbing out
Von Roll	Solid profile, further development of older systems	today’s standard for new builds and conversions

For observation this means: if you’re standing at a mountain railway, the shape of the rack in the track alone tells you which system you’re dealing with. How to work through such features systematically in general is described in the guide to identifying locomotive classes.

Mixed operation: the German speciality

Pure rack railways run in rack engagement from the first point to the last. On routes with only one steep section, that would be uneconomical – so mixed operation was built instead: adhesion drive on the level parts, rack only where it gets steep.

For the vehicles that means considerable extra effort. They need both drive types, plus controls that master the transition, and additional braking equipment for the descent. These very special designs are the reason the Reichsbahn reserved a class number of its own for them instead of fitting them into the existing bands.

The comparison with neighbouring special categories is worthwhile: the Class 98 grouped together branch-line locomotives, meaning vehicles for lightly built secondary lines, while the Class 94 shows how far you can get with pure adhesion and five coupled axles.

Where you can experience rack operation today

There’s no scheduled rack operation left on the German state railway network. What there is instead are tourist mountain railways with their own fleets, plus museum operators that show historic rack vehicles.

• Mountain railway operators directly. Timetables, season dates and closures sit with the operator – and so does whether a historic vehicle is being used.
• Museum fleets and collections. Rack locomotives are rare and stand correspondingly prominently in the fleets that own them.
• Special events. Anniversaries and vehicle rallies are often the only chance to see such a vehicle in motion.
• Community reports for anything short notice and off-schedule.

Which distances and rules generally apply is summarised in the article on keeping a safe distance from the track – it applies on a mountain route just as much as on any main line.

Photo tips on rack routes

The subject of a rack railway is the gradient. If you don’t get it into the picture, you’re photographing an ordinary narrow-gauge railway.

Make the gradient visible. Include a reference line in the shot – a mast, a building, the horizon. Without a reference, even a dramatic incline looks flat in a photo.

Show the rack. A low viewpoint looking along the track makes the rack visible. That’s the detail that explains the shot.

Watch the light in mountain terrain. Valleys fall into shadow early, and slopes glare. The usable time windows are shorter than in flat country – plan them in advance rather than improvising on site.

If a historic steam vehicle is in service, the usual rules of steam photography apply on top: backlight makes steam three-dimensional, cold weather amplifies the effect. The details are covered in the guide to steam train photography.

Common mix-ups

Verdict

The Class 97 is the number that, in the German steam locomotive system, stands for a principle rather than a type. Rack locomotives solve a problem that more boiler output can’t solve: past a certain gradient, the physics of adhesion drive runs out, and only a positive engagement helps from there. On the state railway network this chapter is closed; anyone wanting to experience it travels to a mountain railway or waits for a museum working – and looks just as closely at the rack as at the locomotive.