Key takeaways
- The 800 in the type name is a power class in horsepower, not a statement about the locomotive's tractive effort.
- For shunters, adhesive weight is what counts: what a locomotive can start depends on the weight on the powered axles, not on the engine alone.
- BB stands for two two-axle drive groups – four powered axles, split across two bogies.
- The UIC type code 98 marks diesel shunting and light locomotives, while 92 stands for diesel main-line locomotives.
- Livery, keeper and location can change – the reliable identity comes from the builder's plate.
Contents
Fact file
| Vehicle type | Heavy diesel shunting and industrial locomotive |
|---|---|
| Manufacturer | Krauss-Maffei, Munich |
| Type key | Number = engine power in hp, appended letters = wheel arrangement |
| Wheel arrangement | BB – two two-axle bogies, all four axles powered |
| UIC type code | 98 (diesel shunting and light locomotive) |
Identifying features
Is this really the class in front of you?
- Four powered axles in two separate running gear groups, usually bogies
- Box-type body with a bonnet and shunting cab with good all-round visibility
- Sturdy buffers, heavy drawgear and shunting steps at all four corners
- Side louvres over half the bonnet length for engine and gearbox cooling
- Builder's plate showing manufacturer, type designation, works number and year built
- Setting: port, works and private siding railways with heavy wagon groups
Updated: August 2026 – The type name of an industrial locomotive almost always contains a horsepower figure. For the Krauss-Maffei M 800 BB that’s the 800 – and it says less about its capability in shunting service than you’d expect. This page explains what the number means, why adhesive weight matters more for shunting locomotives, and how to reliably identify the type in the field.
Spotted a heavy shunting locomotive?
Note the date, location and works number straight away – with industrial locomotives that's the only reliable trace.
What is the Krauss-Maffei M 800 BB?
The Krauss-Maffei M 800 BB is a four-axle diesel shunting and industrial locomotive. The name follows the scheme common in German industrial locomotive building: number equals engine power class in horsepower, appended capital letters equal wheel arrangement. BB stands for two two-axle drive groups – four powered axles, split across two bogies. Krauss-Maffei’s rolling stock business passed to Siemens Mobility in the late 1990s – vehicles from the old industrial locomotive programme therefore carry the plate of a manufacturer that no longer exists in that form.
In the European numbering system, such vehicles fall under type code 98: diesel shunting and light locomotives. The difference from code 92, diesel main-line locomotives, is not a question of size but of purpose and registration. How the twelve-digit number as a whole is structured is explained in the article on the UIC number and its check digit.
What the horsepower figure really tells you
Engine power is an easily marketable figure, but it’s not the decisive one for shunting service. A shunting locomotive spends most of its operating time at low speed and above all has to do one thing: get a heavy wagon group moving from a standstill.
Power = work per time
The horsepower figure describes how much the engine can deliver continuously. It becomes important when a locomotive is meant to cover longer distances or gradients under load.
Tractive effort = force at the drawhook
What the locomotive can actually pull is limited by the adhesion limit between wheel and rail. Beyond that the wheels slip – regardless of how big the engine is.
Adhesive weight = the weight on the driven axles
The more mass rests on powered axles, the more tractive effort can be transmitted. That's why shunting locomotives practically always have all axles powered.
That gives you a rule of thumb that helps in the field: if you see a compact but noticeably heavy-looking locomotive, that’s no coincidence. Shunting locomotives are deliberately built massive – ballasting is a design decision for this vehicle class, not a drawback.
Never compare horsepower figures between manufacturers
The number in the type name is a programme tier of the respective manufacturer, not a standardised measurement. An 800 tier from one manufacturer is therefore not automatically equivalent to an 800 tier from another.
BB or C: what the design means in operation
In favour of the BB design
- four powered axles spread the mass across more axle loads
- bogies run more smoothly at higher speed than a rigid frame
- high adhesive weight at a reasonable axle load
- suited to long, heavy wagon groups and transfer runs
Against it
- more complex to build than three-axle locomotives with a rigid frame
- more space required, less suited to very tight works sidings
- more involved running gear maintenance
- higher weight can exceed the axle-load limits of old track
| Task in operation | BB locomotive better suited | C locomotive better suited |
|---|---|---|
| Transfer between works and network | yes | only for short groups |
| Shunting on tight works radii | limited | yes |
| Breaking up heavy block trains | yes | rarely |
| Repositioning single wagons | possible, but oversized | yes |
| Operation on light track | depends on axle load | usually uncritical |
Comparable four-axle designs can be found in the Krauss-Maffei M 1200 BB, the Gmeinder D 100 BB and the MaK G 1100 BB – all built to the same naming scheme.
Collect wheel arrangements systematically
If you consistently note BB, C and B, you'll soon recognise designs at a glance.
Observing and photographing
Heavy shunting locomotives work where block trains are handed over and broken up. That means transfer sidings, dock basins and works entrances – areas with a high level of danger.
Shunting means: no warning, no signal
Vehicles are moved unannounced during shunting, often pushed, without any signal indicating the movement. Parked wagons can start moving at any time. Works, port and private siding railways are private property. Observe only from public paths, bridges or platforms.
Photographically, the side view is essential: it shows both running gear groups and makes BB distinguishable from C. A three-quarter view additionally captures the front and bonnet shape. Because the surroundings are often grey and low in contrast, it pays to pay attention to light and background – the basics are covered in the guide taking good photos of trains, and matching location strategies in the marshalling yard guide.
Why shunting locomotives are geared so low
A detail that quickly stands out when observing: shunting locomotives don’t just run slowly, they’re built for it. That’s a deliberate design decision with several consequences.
- Gear ratio. A short ratio delivers plenty of tractive effort at low speed – and at the same time limits the top speed.
- Continuous operation at low engine speed. The engine works for hours at low load with many load changes, not at a constant operating point.
- Frequent direction changes. The drivetrain and brake are designed for constant reversing, not for long runs.
- Visibility over speed. The cab is optimised for all-round visibility, because runs are made pushed and by sight.
For observers this has a practical benefit: you can often tell the vehicle type from a distance just by how it moves. A locomotive working at walking pace with frequent direction changes and repeated stops is, with high probability, a shunting rather than a main-line machine – regardless of how large it looks.
This very design is also the reason why such vehicles get their own category in the European numbering system. The type code 98 doesn’t describe a size class but a mode of operation: vehicles built and registered for shunting and short transfers, not for train service on the open line.
Common mix-ups
It suggests a BB shunting locomotive if …
- four axles run in two separate running gear groups
- no coupling rods connect the axles
- shunting steps, a running board and heavy draw and buffing gear are present
- the builder's plate names an industrial locomotive type with BB
Look more closely if …
- you only see the front end and can't judge the running gear
- side skirts hide the axles
- the locomotive has been rebuilt and details don't match the build year
It's not a BB locomotive if …
- three axles sit in one continuous frame – that would be C
- four axles run in a rigid frame with coupling rods – that would be D
- the vehicle number begins with 92 and the locomotive carries main-line equipment
Conclusion
The number in an industrial locomotive’s type name is a classification feature, not proof of performance. For the Krauss-Maffei M 800 BB, the more important piece of information is the wheel arrangement: four powered axles, two running gear groups, high adhesive weight. That’s exactly what lets you identify the locomotive in the field – and exactly what it was built for.
And one more point that often gets overlooked when comparing with main-line vehicles: shunting locomotives are procured for availability, not for top figures. An operator needs a machine that starts every day, moves every wagon group and can be maintained with reasonable effort. That’s precisely what the design, gear ratio and mass are geared towards – and that’s why the horsepower figure in the type name says so little about a vehicle’s quality.
In short
Horsepower figure equals power class, BB equals four powered axles in two groups. For shunting service, adhesive weight is what counts – and you can see that from the design, not from the type name.
Keep track of works locomotives
Type, wheel arrangement, works number and date in one place – that's how chance finds turn into a proper archive.
Summary
- Krauss-Maffei offered four-axle shunting locomotives for operators that needed to move heavy, long wagon groups.
- The horsepower figure in the type name describes engine size; for shunting work, tractive effort and axle load are the practically more important figures.
- The BB wheel arrangement is the quickest and most reliable identification feature of this vehicle class in the field.
- Works and port railways are private property – observe only from publicly accessible locations.
Frequently asked questions
What does Krauss-Maffei M 800 BB mean?
The name comes from the Munich manufacturer's type programme. The number 800 denotes the engine power class in horsepower, the letters BB the wheel arrangement: two two-axle drive groups with four powered axles in total. So the name describes the power class and the running gear, not the specific configuration of an individual vehicle.
Does the horsepower figure say anything about tractive effort?
Only indirectly. Engine power determines how much work can be done per unit of time. The starting tractive effort of a shunting locomotive, by contrast, depends largely on adhesive weight – the weight resting on the powered axles – and on the coefficient of friction between wheel and rail. A heavy locomotive with a smaller engine can start a heavier load than a light one with a big engine.
What is adhesive weight?
Adhesive weight is the share of the locomotive's weight resting on powered axles. On shunting locomotives all axles are usually powered, so adhesive weight and service weight coincide. The higher it is, the more tractive effort can be transmitted to the rail before the wheels start to slip.
Why do shunting locomotives often have all axles powered?
Because they have to start from a standstill and need the full available mass as adhesive weight to do so. An unpowered carrying axle would tie up weight without contributing to tractive effort. On high-speed main-line locomotives the calculation looks different – there, ride quality and axle-load limits play a bigger role.
Why do such locomotives carry the type code 98?
The twelve-digit European vehicle number begins with a type code for traction vehicles. 98 marks a diesel shunting or light locomotive, 92 a diesel main-line locomotive. What matters is the vehicle's purpose and its registration, not its size or age.
Where do you encounter a four-axle works locomotive?
Above all where heavy wagon groups are moved: on port railways, in steel and chemical works, and on private sidings of large industrial plants. These areas are almost always private property. Keeper and location also change regularly, because industrial locomotives are traded and leased.
How do I tell BB apart from D?
With BB, the four axles sit in two separate running gear groups that are recognisable as distinct assemblies under the body. With D, all four axles run in one continuous rigid frame, usually with coupling rods. A side-on photo settles the question in seconds.
How do I properly document such a locomotive?
With works number, date, location and a side-on photo. Because paintwork, markings and keeper change, the dated sighting is the real information. If a twelve-digit vehicle number is present, note it as well – it places the vehicle in the European register.
Log your sighting of the Krauss-Maffei M 800 BB
Date, location and vehicle number logged in seconds – and visible to the community.
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Krauss-Maffei M 1200 BB
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