Class 557 (CAF Civity BEMU)

Updated: August 2026 – A multiple unit with its pantograph raised, running on a line without overhead wires – that’s not a mistake, it’s the giveaway of the new battery generation. Class 557 from the Civity family built by the Spanish manufacturer CAF belongs to this group. This page shows you how to place BEMU multiple units confidently and how to tell them apart from everything else.

What is Class 557?

Class 557 is a battery-electric multiple unit (BEMU) for regional services, built on the Civity platform of the Spanish manufacturer CAF. It runs under overhead wire like an ordinary electric multiple unit, charging its energy store as it goes, and then covers non-electrified sections on battery power.

That makes the 557 representative of an entire vehicle generation. For decades the rule was: overhead wire means electric multiple unit, no overhead wire means diesel railcar. Battery trains break up that assumption – and briefly make identification in the field harder, until you know the decisive feature. Anyone who works through the basic sequence of steps for identification still gets there quickly; the guide to identifying classes explains it step by step.

The designation itself works on two levels. Civity is the manufacturer family’s product name, comparable to FLIRT at Stadler, Talent and Coradia at Alstom, Mireo and Desiro at Siemens. 557 is the German class designation. The 5xx block is used for multiple units with alternative traction, while purely electric regional multiple units sit in the 4xx and 14xx blocks. And above all of that sits the UIC type code 94 as the first two digits of the twelve-digit vehicle number – it marks the vehicle as an electric multiple unit, regardless of whether the energy comes from the overhead wire or from the battery. How those twelve digits break down is explained in the article on reading the UIC number on a vehicle.

Three steps to a confident BEMU identification

Where battery multiple units fit operationally

BEMU vehicles are not a universal solution but an answer to a specific network problem: routes that are partly under wire and partly not. For observation, that means they turn up in predictable places.

Route type	Expected vehicle	Why
Fully electrified main line	Electric multiple unit or locomotive-hauled train	Overhead wire present, no store needed
Partly electrified route with a gap	Battery multiple unit (BEMU)	Charges under wire, runs on battery across the gap
Branch line with no overhead line at all	Diesel railcar or battery multiple unit with charging point	Depends on whether charging infrastructure exists
S-Bahn network with its own power supply	Specialised S-Bahn class	Own platform heights and train protection
Transition from main line to branch line	System-changeover point, often with a stop	This is where the train raises or lowers its pantograph – the best photo moment

The last point is the most interesting: system-changeover points are the only situation where you can actually watch a battery train switching over. Anyone who knows the location gets the shot of a pantograph just being lowered under the ending overhead wire.

Photo tips for battery multiple units

A BEMU looks in a photo like any other regional multiple unit – unless you show exactly what makes it special.

• Get the roof in the shot. A slightly elevated viewpoint or a shot from further away with a telephoto lens makes the battery containers visible. The classic view from the platform below doesn’t show them.
• Look for the end of the overhead line. The last mast before the wire-free section is the most compelling shot this vehicle has to offer.
• Shoot three-quarter, not head-on. Front and side together show the nose shape, door layout and number – everything you need for later identification.
• Keep a safe distance. The platform edge and the track area are off limits; a better angle never justifies a step past the safety line.

Which focal length makes sense for shots like these is covered in the guide to the best telephoto lens for railway photography. And because new vehicle series in the rollout phase grow especially fast, it’s worth logging every unit straight away – the guide to logging sightings shows you how to do that systematically.

Where battery multiple units are changing the vehicle landscape

The introduction of the battery generation is the biggest shake-up in German regional rail since locomotive-hauled local trains were replaced by multiple units. For vehicle identification, that has several consequences that go beyond any single class.

• The old rule of thumb no longer applies. For decades the rule was: overhead line means electric, no overhead line means diesel. Battery vehicles break that assumption – and hydrogen vehicles do so too, in a different way.
• The number block is shifting. Vehicles with alternative traction are listed in the 5xx range, while purely electric regional multiple units stay in the 4xx and 14xx blocks. An unfamiliar 5xx number is therefore a strong clue.
• The roof becomes the main feature. Battery modules, cooling units and power electronics need space and almost always sit on top on these vehicles. Anyone who only photographs the front misses exactly the decisive detail.
• System-changeover points become interesting. At the boundary between electrified and non-electrified sections, something happens operationally that didn’t happen before.
• Diesel vehicles are gradually disappearing. Anyone who still wants to document particular diesel railcars shouldn’t put it off – here too, fleets change.

In practice that means: note at every sighting whether the pantograph was raised or lowered, and whether an overhead line was hanging over the track. Those two pieces of information cost nothing, but later make the difference between an arbitrary train photo and a documentation of the traction concept. Because several manufacturers are currently delivering in parallel, a very varied vehicle landscape is emerging in a short space of time – and it’s exactly these transitional phases that people remember later.

Common mix-ups

Specifically, there are three vehicles the 557 is most often confused with in practice. The Siemens Mireo Plus B is the direct competitor and likewise a battery train – it’s set apart by its much more rounded, smooth-surfaced Siemens nose compared with the more angular Civity front. The Class 563 from the Mireo family belongs technically to the same category and differs mainly in class designation and window layout. And the Alstom Coradia iLINT looks similar at first glance, but runs on a hydrogen fuel cell and has no pantograph at all – that one feature sets it apart beyond doubt.

Verdict

Class 557 is a good example of how the old identification rules are shifting right now. Overhead wire no longer automatically means electric multiple unit, and no overhead wire no longer automatically means diesel. Anyone who looks at the roof, listens for whether an engine is running, and checks the class identifier still stays confident within seconds.