Key takeaways
- The Re 450 is an S-Bahn locomotive: designed for closely spaced stops and fast acceleration rather than top speed.
- It runs as a set: locomotive, double-deck coaches and driving trailer together form the double-deck push-pull train.
- Identify the train, not just the locomotive: anyone who places the coach set has automatically placed the locomotive too.
- The number 450 follows the Swiss scheme in which the first digit gives the number of powered axles.
- Lines and diagrams change with every timetable change – check the current picture.
Contents
Fact file
| Vehicle type | Four-axle electric locomotive for S-Bahn services |
|---|---|
| Railway administration | Swiss Federal Railways (SBB) |
| Procurement | from the late 1980s |
| Wheel arrangement | Bo'Bo' – four axles, all powered |
| Electrification system | 15 kV / 16.7 Hz AC |
| Mode of operation | Fixed part of a push-pull train set with double-deck coaches and a driving trailer |
| Modern class | Re 450 – the first digit stands for four powered axles |
Identifying features
Is this really the class in front of you?
- Four axles in two bogies, all powered
- Runs practically always as part of a double-deck push-pull train, never solo
- A driving trailer sits at the other end of the train – the train reverses direction without running the locomotive around
- The locomotive body's design matches the double-deck coaches in colour and form
- Vehicle number starts with 450
- Typical environment is dense suburban traffic, not long-distance services
Updated: August 2026 – Some locomotives are best identified by not looking at the locomotive at all. The SBB Re 450 is such a case: it is inseparably tied to the double-deck push-pull train in SBB S-Bahn service and practically never runs alone. This page shows you how the set is put together, why that is an advantage for identification, and what to watch out for when photographing it.
S-Bahn sightings count too
Local services are under-represented among spotters – yet sets and liveries change here just as much as in long-distance traffic.
What is the SBB Re 450?
The Re 450 is a four-axle electric locomotive of the SBB for S-Bahn services, procured from the late 1980s onwards. All four axles are powered, and it runs under the Swiss standard system of 15 kV at 16.7 Hz.
What sets it apart from other locomotives is not the technology in detail but the operating philosophy. The Re 450 was not designed as a free-roaming haulage locomotive that runs in front of a freight train today and an express train tomorrow, but as a fixed part of a defined train set: locomotive, double-deck coaches, driving trailer. That unit is the actual vehicle type, with the locomotive only one component of it.
For S-Bahn operation, that is the right answer. With stops a few minutes apart, journey time is not decided by top speed but by acceleration and dwell time. A set that reverses direction at the terminus without running the locomotive around saves measurable time on every single diagram.
Identify the train, not the locomotive
For push-pull trains, the fastest route to identification runs through the train’s make-up. Anyone who recognises that has automatically dealt with the locomotive too.
Look for double-deck coaches
Two rows of windows stacked on top of each other are the most striking feature. They immediately rule out all single-deck local trains.
Compare both ends of the train
A locomotive at the front, a coach with cab windows at the rear: that is the signature of a push-pull train. Two locomotives or two matching ends point to something else.
Check whether the traction is bundled
If the equipment sits in a separate locomotive body, it's a locomotive with a coach set. If the traction is spread across the whole train, you're looking at a multiple unit.
Finally, read the number
If the locomotive's vehicle number starts with 450, the identification is confirmed. Everything before that is a clue, this is the proof.
The direct point of comparison is the Regio-Dosto RABe 511: also double-decked, also in regional service, but built as a continuous multiple unit without a separate locomotive. And in long-distance traffic, the IC2000 driving trailer shows that the push-pull principle is used there too.
Push-pull train, multiple unit, loco-hauled train – the difference
Three types of construction that can stand side by side at a station and differ considerably in how they operate. The following comparison helps you place them.
| Feature | Push-pull train with Re 450 | Multiple unit | Classic loco-hauled train |
|---|---|---|---|
| Traction | bundled in a separate locomotive | spread across the train | in a separate locomotive |
| Reversing direction | via driving trailer, no run-around | no run-around | locomotive must be run around |
| Opposite end of train | driving trailer with cab | power car or cab car | coach without a cab |
| Separability | locomotive can in theory be uncoupled | fixed-coupled unit | freely combinable |
| Typical field of use | dense suburban traffic | local and long-distance services | long-distance services, special trains |
It pays to look at the other end of the train
Many misidentifications happen because only the locomotive is looked at. A step to the side and a glance at the opposite end of the train usually answers more questions than any detail on the front.
Log sets properly
Locomotive, number of coaches, driving trailer: log the whole set and you can actually trace diagrams later.
Where and how to photograph the Re 450
S-Bahn traffic has a big advantage for photographers: it runs at close intervals, so you get plenty of attempts. The downside is the train length – double-deck sets rarely fit completely in the frame.
Work from the end of the platform
There you get an angled view of both the front and the side without needing the whole train in shot. In the middle of the platform, often only a section fits.
Plan for the height of the train
Double-deck coaches are tall. Standing too close causes converging verticals – a bit more distance and more focal length solves the problem.
Use the frequency for repeat attempts
With dense traffic you can practise the same shot several times. Use the first train as a test shot and the second for the result.
Respect the safety line
The area behind the platform edge is track territory and therefore off limits. Anything that should look closer, achieve through focal length.
How to check a station in advance for light, track layout and vantage points is described in the guide to choosing a photo spot on a platform. For planning a whole session, the article on planning a station spotting tour is worth a look, and for finding out what’s currently running, the guide to tracking trains live in Switzerland.
Why S-Bahn vehicles are built differently
In long-distance traffic, top speed decides journey time. In S-Bahn service it doesn’t – and that changes the design fundamentally.
Work it out: with stops two to three kilometres apart, a train never even gets to reach its top speed. It accelerates, runs briefly, brakes again. What determines the timetable are therefore three quite different quantities: acceleration, braking deceleration and dwell time at the platform.
Each of these quantities leads to a design decision. High acceleration requires traction on all axles and enough adhesive weight. Short dwell times require wide doors in the right places and a well thought-out interior layout. And doing away with running the locomotive around at the terminus – the push-pull principle – saves several minutes on every single diagram, which can add up over the day to a whole extra vehicle rotation.
Double-deck coaches come into it because platform length in suburban traffic is limited. If you need more seats but can’t get longer, you build upwards instead.
What this means for spotting
Design features tell you the purpose. Traction on all axles, many wide doors and a driving trailer at one end together add up to a local-service vehicle – even before you've read a line designation.
Common mix-ups
It points to a Re 450 if …
- a four-axle locomotive is coupled to a double-deck coach set
- a driving trailer with a cab sits at the other end of the train
- the train is running in dense suburban traffic
- the vehicle number starts with 450
Look more closely if …
- you only see one end of the train and can't be sure of the build
- a special livery obscures the familiar design
- the train is standing at the station and the locomotive is hidden behind a pillar
It is not a Re 450 if …
- the train is built as one continuous unit without a separate locomotive – that's a multiple unit
- the number starts with 420, 430 or 460
- the coaches are single-deck
For direct comparison, it’s worth looking at the universal Re 420: the same number of axles, but a completely different profile of use. Anyone who can tell the two apart understands just how strongly the job shapes the design.
Conclusion
The Re 450 is the locomotive where you have to identify the train to identify the locomotive. Double-deck coaches, a driving trailer at the other end, dense suburban traffic – these three observations lead to the answer more reliably than any detail on the locomotive body. The number ultimately confirms what the overall impression has already told you. And because line assignments shift with every timetable year, the vehicle number is the only part of your sighting that holds true in the long run.
Bottom line
Four-axle locomotive, double-deck coaches, driving trailer at the other end: that's the push-pull train with a Re 450. A vehicle that only exists as part of a set – and whose lines change with the timetable.
Collect local services systematically
S-Bahn sets change more often than you'd think. With Traintrack you keep track of your sightings.
Summary
- The Re 450 shows how a locomotive can be built entirely around one specific train set.
- For field identification, the whole train counts for more than the single vehicle.
- Its field of use is dense suburban traffic, where acceleration and door-change times set the timetable.
- Because line assignments shift, the vehicle number is the only stable reference point for a sighting.
Frequently asked questions
What is the SBB Re 450?
The Re 450 is a four-axle electric locomotive of the SBB for S-Bahn services. It was procured from the late 1980s and, together with double-deck coaches and a driving trailer, forms a fixed train set, the double-deck push-pull train. All four axles are powered, and the wheel arrangement is Bo'Bo'.
Why do you never see the Re 450 on its own?
Because it is designed as part of a set. The locomotive, double-deck coaches and driving trailer work as a unit; the train can reverse direction at the terminus without the locomotive needing to be run around. You only meet such vehicles solo during transfer moves or in a workshop context.
What is a push-pull train?
A train that can be driven from both ends: the locomotive at the front, a driving trailer with a full driving cab at the rear. The driver simply moves to the other end at the terminus. That saves shunting time and is the decisive advantage over classic loco-hauled trains in dense suburban traffic.
How do I recognise the set at a station?
By the combination of double-deck coaches and a locomotive at one end. At the opposite end of the train sits a coach with cab windows instead of another locomotive. This arrangement is so distinctive that you can identify the train type from a great distance.
What does the number 450 mean?
For Swiss electric locomotives, the first digit of the three-digit class can be read as the number of powered axles. The 4 stands for four powered axles, as with the Re 420, Re 430 and Re 460. The following two digits distinguish the designs from one another.
What is the difference between the Re 450 and a double-deck multiple unit?
The construction. On the Re 450 the traction equipment is bundled into a self-contained locomotive that could in theory be uncoupled. A multiple unit such as the Regio-Dosto spreads the traction across the whole train and cannot be split apart. The difference is visible at once: a locomotive plus coaches in one case, a continuous train body in the other.
Which lines does the Re 450 run on?
On dense suburban services, traditionally around the Zurich S-Bahn. Which lines are actually run with which sets, however, shifts with timetable years, vehicle procurement and refits. Only the current picture from real-time data and your own observation is reliable.
What should I watch out for when photographing S-Bahn traffic?
Platform length and light. Double-deck trains are long and tall, which is why a spot at the end of the platform with a bit of distance usually works better than the middle of the platform. Keep a safe distance from the platform edge and use focal length rather than moving closer on foot.
Log your sighting of the SBB Re 450
Date, location and vehicle number logged in seconds – and visible to the community.
Related classes
SBB Class RABe 511 (Regio-Dosto)
The RABe 511 is the SBB's double-deck electric multiple unit for regional and RegioExpress services. Here's how to read the designation and tell it apart from a loco-hauled push-pull set.
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The Re 4/4 II is the standard electric locomotive of the SBB and is now called the Re 420. This page shows you how to recognise it and what the two designations mean.
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Electric locoSBB Re 465 (BLS)
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Electric locoSBB Re 474 (Vectron CH)
The Re 474 is a four-axle multi-system freight locomotive for the Switzerland–Italy corridor. This page explains electrification systems, naming and recognition features.
Electric locoHGe 4/4
The HGe 4/4 is an electric rack locomotive for Swiss metre-gauge railways. This page decodes the designation and shows what to look for in the field.
Who is behind it
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Tram-Museum Zürich
The Tram-Museum Zürich doesn't sit in a hall on the edge of town, but in a former operational depot on the active network. Historic trams run from here on the same metre-gauge tracks used by scheduled services – a museum that moves right through the middle of operations.
State railwaySchweizerische Bundesbahnen (SBB)
SBB doesn't label its vehicles with a class number but with a combination of letters that codes speed, coach class and type of traction. Anyone who can read Re, RABe and Ee identifies a Swiss vehicle faster than any database lookup.
Where to see the SBB Re 450
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