DM3 Diesel Shunter
The DM3 Diesel Shunter is a 3-axle diesel-mechanical shunter added in the Simulator update. It is a better choice for medium-weight loads that would be overkill with larger engines like the DE6. It is not multi-unit compatible.
The DM3 has non-self-lapped brakes. It also has an engine brake (a compression-release brake, AKA jake brake) which serves as a dynamic brake. It also exhibits a passive engine braking effect; downshifting can be used to decelerate the locomotive.
It is the most fuel-efficient locomotive in the valley (as far as load-rating-to-fuel-consumption) and has very low running costs. It is capable of setting truly massive weight into motion, but has very limited speed.
Operation
The DM3's prime mover is a diesel engine, which is connected to the drive train mechanically through two gearboxes. The engine is connected to the gearboxes via a torque converter, although unlike the DH4, the transmission fluid is dense enough to force the engine to stall, and it controls its torque ratio using the gearboxes.
The gearboxes are shifted manually. The outputs of both gearboxes are multiplied together to get the final ratio of power to top speed. Its lowest gear, 1-1, has excellent torque, and can set pretty much any weight in motion on level ground.
As the gearbox has no clutch, it is advised to disengage the throttle and engine brake before shifting, to avoid damaging the gearbox. If the engine brake or throttle is engaged when shifting, you will hear a grinding/crunching noise.
| Gearbox A | Gearbox B | ||
|---|---|---|---|
| Lever Position | Gear Ratio | Lever Position | Gear Ratio |
 |
1 | |
1 |
 |
1.5 | |
2 |
 |
2.5 | |
2.667 |
| Notes | Lever Positions | Combined Gear Ratio | Top Speed (Flat Ground) |
|---|---|---|---|
| Max Speed |  |
1 | 67 |
 |
1.5 | 45 | |
 |
2 | 33 | |
| Recommended
to skip this gear |
 |
2.5 | 27 |
 |
2.667 | 25 | |
 |
3 | 22 | |
 |
4 | 17 | |
 |
5 | 13 | |
| Max Power |  |
6.667 | 10 |
Notes
- While the gearbox may seem complicated, memorizing lever combinations isn't actually necessary in most cases. It is usually sufficient to know that pulling a lever backwards-- either lever-- will always give you more power, and forwards more speed.
- It may be useful to imagine gearbox B as a range selector (1 being low, 2 being high, 3 being overdrive), rather than simply a second gearbox.
- As it is impossible to disconnect the engine from the drive train while moving at high speed, the train's speed must be limited on downhill slopes. As the train speeds up, the engine, even if at idle throttle, will rev higher and higher since it is mechanically connected to the wheels. Overrevving of the engine causes damage and, eventually, catastrophic failure and explosion.
- It is possible to take off from any gear, including 3-3. 1-2 is a good launch gear for loads under ~500 tons, and 1-1 is advised for anything higher than that.
- Because of the automatic-car-like "creep" when the reverser is put into gear, the rear of the cab being directly above the coupling, and the handbrake being positioned inside the cab under the window, the DM3 is perhaps the easiest locomotive to position smoothly for coupling.
- It has the smallest fuel tank in the game, even smaller than the DE2's (2000 units compared to 1500), as well as the smallest sand tank (250 units).
Trivia
- The DM3 seems to be based on a British Rail Class 03 locomotive, according to appearance and available technical information.
Gallery
One of the first revealed images of the DM3, from the water physics teaser.
One of the first closeup views of the DM3, from the VSync & FPS Limiter teaser.
This is a British Rail Class 04 that could be the template (along with 03) for DM3
A front view of the DM3
A rear view of the DM3
DM3 cab
