[MOC] Derail Valley locomotives (instructions + parts list)

[witchy]

In motion

Derail Valley is a pretty fun train simulator game where you try to avoid getting into trouble while running trains in an environment practically designed to get you into trouble with unreasonable curves, unpredictable weather, uncomfortable gradients, and inconsistent speed limits. You do every task yourself, from setting points to keeping your locomotive fueled, and the time pressure of earning bonuses encourages exciting, reckless and absolutely unsafe practices (surely I can leave two trains running unattended while I couple up another group of wagons, what's the worst that could happen?).

The DM3 resembles the BR Class 03 (and 04) in its layout, but is significantly heavier (around 50t) , stronger (360kW engine power), and faster (roughly 60km/h top speed). Its combination of two 3-speed gearboxes has given it a somewhat undeserved reputation as being difficult to drive, and makes the locomotive capable of pulling unreasonably heavy trains as long as it doesn't need to pull them uphill faster than walking speed.

DM3 guide on youtube

The model is built to BMR standards: 1:48 scale, making the model 7 studs wide, and compatible with both Kadee and magnet couplers at their standard positions. The physical build is still a bit WIP with the Kadee couplers being on their way from across the pond, and I might adjust some details a bit. Instructions, studio file and parts list will be published once I'm satisfied with the physical build.

The model is powered by a Circuit Cube motor with a 12:20 gearing and uses Breckland Bricks wheels and rods. Third-party wheels are necessary for the build; third-party rods can be replaced with ones built from thin liftarms. The wheels must have their pinholes at the correct distance from the axle, so wheels from other suppliers (e.g. Big Ben) may or may not be compatible. The rods at the jackshaft end would fit behind the ladders just fine by the dimensions, but they are slightly bent outwards and there is enough play in the 3/4 pins to let them sometimes hit the ladder. The lights are LifeLites NanoLite LEDs on Circuit Cube adapters.

The build is mostly pretty straightforward, with some elements that are trapped between other parts to hold them in place. The motor is installed between the middle wheels, the battery is in the cab, and the wiring and adapters for the lights have dedicated space under the bonnet but are fiddly to install. The cab roof and bonnet top are designed to detach easily to allow access to the battery. The cost is around £50-60 for the bricks, £30 for the rods and wheels, £35 for the circuit cubes, and £30-35 for the lights.

Studio files, instructions and parts list are at: https://drive.proton.me/urls/PQ8AG1JEXM#mDI70r4fpIh0

Edited March 4 by witchy
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[Selander]

I really like it ! Realistic design and colors.. .the yellow details makes it pop 👌👍🙌

[Feuer Zug]

Nice diesel-hydraulic shunter. I like that you've built it in 7-wide. The colors work well on it too.

[JopieK]

Very nice @witchy. It has obviously some 7760 vibes (including the color). You also made nice use of new(er) parts for e.g. the tail lights.

[cole deveno]

awsome build! where did you find those wheels?

[witchy]

49 minutes ago, cole deveno said:

awsome build! where did you find those wheels?

The wheels are Breckland Bricks, size M/#7 with traction bands (4 flanged, 2 blind). I'm not sure if the traction bands are entirely necessary; the locomotive weighs 319 grams and the cubit motor stalls instead of slipping the wheels, but I haven't bothered testing it without them. Being able to slip the wheels would be prototypical, but being limited by torque instead of adhesion is more practical.

Other suppliers' wheels may also work, if they have the correct spacing of the pin holes to match the 32530s I used for the jackshaft counterweights.

 

1 hour ago, JopieK said:

Very nice @witchy. It has obviously some 7760 vibes (including the color). You also made nice use of new(er) parts for e.g. the tail lights.

The model is a as-precise-as-I-could recreation of the in-game vehicle so the colour was chosen by the developers:

The 1x1 rounded SNOT piece becoming available in light bluish grey was actually one major motivation to revisiting this build. I had made an earlier, 8-wide version whose proportions I was never quite happy with, so when I saw that I could make the lights I wanted I redesigned it according to precise scale measurements. The main missing detail is the air cylinders on the sides, where there just isn't enough room for something that would do them justice. Otherwise the 7-wide build didn't really cause any major problems, and means that the locomotive would look appropriately small next to matching 8-wide rolling stock.

I also tried making a BR Class 03 version of the same chassis, but found that the proportions are actually almost entirely different in subtle ways that would've required through redesign of the frame and drivetrain.

Edited February 10 by witchy

[witchy]

The build is designed to be reasonably sturdy and swooshable (the best place to grab is by the grey plates just front of the rear axle), while partially disassembling in sections held in place by only 3 studs at most to give reasonably easy access to the battery:

There are very few, if any, illegal connections (the protruding contacts on the battery's corners are accommodated by the cab sides being slightly rotated outwards), and apart from the issue of the ladders and side rods (and some slight flimsiness in the cab near the ladders as I accidentally ordered the wrong parts and had to substitute tiles where the design called for 41740 modified plates) there aren't any obvious structural weaknesses or parts that could fall off easily.

[LEGO Train 12 Volts]

The design of this locomotive is perfect, but let me say a few words about the colors: absolutely uncommon and incredibly beautiful ...the yellow totally rock me and the blue then makes it unique.
The work on the lights is first rate ... I would say the icing on the cake!
The video with the locomotive in action is just super!

[Asper]

Great, very realistic model. I like the colour's.

[LegoAlf]

I also like this model very much. The color looks nice and reminds me of the 7760. And it resembles the look of the Class 03 quite nicely.
Interesting to see, how well 7-wide can be used to build locomotives and waggons. I tried some before myself, but the extra stud in size make them look a bit oversized compared to my standard 6-wides.

Anyway, a very nice locomotive - congratulations!

 

[witchy]

I actually tried making a Class 03 with the same chassis, but various proportions are just too inaccurate in this one so I rejected it. As an example, in Class 03 the rear axle should be behind the front of the cab, unlike in the DM3 where it is slightly forward of the cab. I find that these small shunters are really sensitive to subtle proportions or else they will look just wrong in some way or other.

 

[_TLG_]

Cool build with many interesting techniques!

[witchy]

I ended up also making DM1U, an old railbus that was turned into a utility vehicle for the railway company. Motorised with circuit cubes, designed for compatibility with both Kadee and magnet couplers, non-driven rear axle is intened to be compatible with ball bearings, and an unpowered build can be done without any third-party parts.

There is one illegal connection (slight interference of stud logo) in the front, otherwise I'm not aware of illegal or particularly sketchy techniques. The printed tiles on the sides are designed to be easily replaceable by a sticker on a 1x3 brick instead. The roof is offset towards the rear by half a plate to create a refined shape:

[zephyr1934]

7 hours ago, witchy said:

Clever trick with the awning on the rear of the cab

[witchy]

Next in line turned out to be the BE2 battery-powered microshunter, very similar to LEW EL 16 but with a different cab design in the game. Doing the cab corners for this one was very interesting, with the small dimensions leaving litttle space for the complicated angles.

This little thing is powered with a Studly Trains micro motor and a Circuit Cubes battery, with a 2:1 gearing ratio further slowing it down appropriately for simple shunting tasks.

[XG BC]

On 2/24/2025 at 8:29 PM, witchy said:

I ended up also making DM1U, an old railbus that was turned into a utility vehicle for the railway company. Motorised with circuit cubes, designed for compatibility with both Kadee and magnet couplers, non-driven rear axle is intened to be compatible with ball bearings, and an unpowered build can be done without any third-party parts.

nice! ever since i saw the video from the youtuber hyce that played derail valley using this DM1U wanted to build it, you were faster than me (no problem, mine might have been 6 wide or even 4 wide anyways).

[XG BC]

sorry to Hijack this post, but here is my mini model of it:

 

 

 

[witchy]

Cute!

[Sebeus I]

Absolutely love it! Excellent choice of parts. The wheels are custom I presume?

[witchy]

15 minutes ago, Sebeus I said:

Absolutely love it! Excellent choice of parts. The wheels are custom I presume?

The wheels on the DM3 are custom (Breckland Bricks medium), and the rods are Breckland Bricks too. Everything else apart from the electronics is Lego. On the DM1U and the BE2 the wheels are normal Lego train wheels.

Edited March 2 by witchy

[XG BC]

2 hours ago, witchy said:

Cute!

thanks! i had already built a vt98 a couple of years back (look into trains in 4 wide here) so i just needed to delete the rear parts and add the bed in their place, i just HAD to do it!

[witchy]

The instructions and parts list for the DM3 are out: https://drive.proton.me/urls/PQ8AG1JEXM#mDI70r4fpIh0

[LMGbros 772]

Wonderful little shunter! I love how you were able to pull off the rear windows with those bracket plates. The light blue color looks good as well!

[FerroCompi]

Hey by any chance may I have instructions on how to make the DM1U? Thank you!

Edited July 10 by FerroCompi
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