Train Sim World

Train Sim World 2- Making the DB BR 612 DMU

Tharandter Rampe: Dresden – Chemnitz is coming soon! We spoke to some of the developers to learn more about the routes iconic unit, the incredible DB BR 612 DMU, Train Sim World 2’s very first tilting train!

Tell us a little about yourselves!

Tom: I'm Tom, I'm the Lead Vehicle Artist for Train Sim World at Dovetail Games. I support a talented team of artists who build the rolling stock that we all enjoy driving and interacting with.
Maik: My Name is Maik Goltz, and I have been working on the Train Simulator and Train Sim World franchises for about 10 years now. Besides my personal DLC work, I work as a contractor for Dovetail Games. Having had a hand in making a lot of DLC content happen in the past, for both Train Simulator and Train Sim World. I’m also the brains behind TrainSim-Germany.

What has been you or your team’s involvement in creating the DB BR 612 DMU?

Tom: I have been overseeing the great work being done by both our internal and external artists involved in producing the DB BR 612 DMU, in conjunction with on-going communication with a few external collaborators who have been forthcoming with information and reference material, which as always makes a massive difference when it comes to producing rolling stock and it’s something we’re incredibly grateful for.
Maik: For the DB BR 612 DMU I have been doing the setup and audio work. This means I created a whole new train from scratch including all the SimuGraph work and the tilting system integration. If it's a visible component that’s my responsibility. My involvement in the audio work means recording brand new sounds from a real DB 612, then editing it, before implementing the best mix into the build.

What is unique about this loco?

Tom: The DB BR 612 DMU gets to boast a few firsts for Train Sim World. Not only is it our first German DMU (Diesel Multiple Unit), it is also our first tilting train to boot! It also features some interesting touches such as the Kinderspielecke (Family area). This features child-friendly graphics from DB and is something we’ve not featured in any previous German rolling stock before.
Maik: The most obvious things are the tilting mechanism, also known as Neigetechnik (tilting technology) or GSt (track curve-dependent car body control), as well as GNT, the new safety system that works together with the tilting. The DB BR 612 DMU can drive faster than the usual max speed which normal German trains follow. By leaning into curves by up to 8°, the centrifugal forces that passengers feel in the train are reduced. This allows the DB 612 to drive up to 20 km/h faster in curves than traditional, non-tilting stock.

A tilting train! That’s really interesting. What new processes did you utilise when compared to creating a non-tilting train?

Maik: This was actually a brand new area for me to get my teeth into. I’ve never done anything that tilts before, neither in Train Simulator or Train Sim World. So, first I needed to do in-depth research and consider how I was going to recreate it before I started to work on the train. I read some technical descriptions of tilting systems as well as the manual for the DB 612 itself, getting an idea of how it is driven and the physics behind different key values like speeds and forces. The general workflow for creating a train was not much different except for one aspect, all the components that form the train above the bogies need to be able to tilt along with the train's body as well, understandably this caused some headaches, but in the end, I got it working well. The tilting animation is really smooth and eye-catching to watch.

Why do some trains tilt and how do they stay safely on the tracks at speed?

Tom: The tilting mechanism is used specifically to keep the train on the track whilst traversing curvature at high speeds without impacting comfort levels for the passengers onboard. As the train approaches a curve at high speed, the body tilts into the curve via a set of actuators mounted between the bogies and the body. The technology was introduced to facilitate higher running speeds on lines that weren’t built with high-speed running in mind. The tilting allows safe operation at high speed without requiring new lines to be built or existing lines to be rebuilt, both of which can be cost inhibitive.
Maik: A good question, the honest answer would be “mother nature”. Generally, tracks in Germany, are laid so that higher-speed trains can easily run faster on them as allowed. So, the speed profile for passenger trains is applied with passenger comfort in mind, rather than the speed a train could derail in a curve. Of course, trains will derail when they are travelling too fast in curves, but each curve is calculated with a good speed threshold, from the max allowed speed to the speed where it is likely to cause a derailment. These enforced maximum speeds can be ignored by tilting trains on routes fitted with the appropriate equipment. The Tilting Mechanism allows the train to travel above the conventional max speed whilst maintaining the comfort of the passengers. Of course, the bogies don’t tilt and run as normal on the tracks, they do have corresponding forces applied to them when at higher speeds, but the train is built for doing exactly this. It will not derail if it stays under the max speed for the tilting run, even if it may look that way.

What new gameplay can players look forward to with the DB BR 612 DMU?

Maik: With the tilting, a whole new driving experience is there for the player to experience. When going into sharp curves with the high speeds it looks like the train would tip over, that’s not going to happen but takes some getting used to. It’s a bit different than only having superelevated tracks. The additional 8° of tilt is kind of scary the first time you see it. We are talking about nearly 14° of tilting to the side. That’s doesn’t sound like much but feels massive when you are in the cab, and makes driving it lots of fun. Wait until you see it from the outside, it looks fantastic.

Have you or your team come across any challenges while creating this loco?

Tom: We’re still not quite at a point where we can readily fly out and survey trains in other countries just yet, so that remains an ongoing challenge and this was no exception. The curvature of the nose is deceptively straight-forward looking at first glance, but required some back and forth to get it to a place we were happy with.
Maik: As mentioned above, there were some new technical challenges to master. I put a good amount of time into the simulation of the 3-stage fluid transmission, and the hydraulic braking, both work in interesting ways due to the DB 612’s other unique features and design. The DB BR 612 DMU’s hydraulic braking is totally different from any I had previously produced including the G6 Shunter that I had recently worked on for Train Sim World 2. Then the brake blending was challenging because the DB 612 is doing some different things here too to other trains. You can use the hydraulic braking with the two different levers in the cab, but it acts differently depending on which lever you use. This was quite tricky as you can imagine.
Of course, the tilting system overall was a real challenge that needed to be achieved visually and had to tilt smoothly. Lots of parameters are “running around” in the background to achieve that. Some other challenging aspects were the engine group start-stop control and a few of the multiple-unit systems like the per-unit battery and high voltage lines.

What have you or your team enjoyed most about recreating the DB BR 612 DMU?

Maik: Simply put, I enjoy what you can do with Train Sim World 2 to create a train in nearly all aspects, and as close to the real one as possible. Oh, and getting to drive it for a thousand kilometers before anyone else can do it! My work on some of the systems is not always enjoyable in terms of having fun creating the stuff, however, the hard work and challenges it presents along the way mean I learn lots of new ways to improve and implement these complicated systems. That gives me a good feeling for my future work on Train Sim World 2 content.
Tom: Other than the fact we were able to introduce some new elements such as tilting with this release, we were also able to act on additional suggestions from collaborators, such as the coupler covers that serve to protect the couplers in winter when not in use in multiple set operation. These are configured to be present on sets running in colder weather and removed in warmer weather, much as they are in the real world. Small details like this are great little touches to include.
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Train Sim World
1 Dec
Train Sim World 2- Making the DB BR 612 DMU