Developer Interview: Train Sim World 4

There are a couple of key things we wanted to really deliver well on for this release; the first was to have new and exciting content that wasn't like the routes and trains we'd done before, introducing all new operators to the franchise and a new country really put us on the right path for that. The East Coast Main Line has long been requested by our players, so it's been great to finally get that pure high-speed experience out to them as well since we haven't done anything like it before with the UK content.

The second thing [we] wanted to do well on was extending and enhancing the actual gameplay experience; last year, we focused a lot on the visuals in the game, so this year, we wanted to give people new ways to enjoy their collection and really take control of their experience. Free Roam and Photo Mode are two key features that really do this well, I think, and are certainly proving to be player favourites.

Lots of research! The team [spends] a lot of time looking at the trains in detail, doing a lot of digging to understand the nuances of a train behaviour, or looking into the routes in detail, sometimes even going into their histories to understand why things look the way they do so they can better [comprehend] what areas are more or less important to recreate them.

Without a doubt, it's getting enough detail on the trains themselves to deliver them convincingly and to the level our players expect. Access to the real operators and maintenance manuals makes it much easier to get the required level of knowledge, but even then, they often miss crucial information we need, or in a couple of cases, incredibly, we've found them to be wrong; train setups change over the years, and the manuals tend to change less often!

I think of all the challenges, though, our audio team has by far the most difficult task. While our art teams have mastered recreating a train by just looking at a range of photographs, and the simulation team have been able to build up enough domain knowledge to make a solid estimate to fill in gaps in the research, the audio team are very reliant on getting access to the real train so they can capture the recordings. While some operators are very supportive of this, others are simply too busy or can't make it work within their safety guidelines, so the challenge for the audio team then escalates greatly, having to create something out of nothing and still meet our player expectations.

There are several teams that are responsible for creating the routes.

The "Infrastructure Team" are responsible for recreating the technical aspects of the route, starting with the base landscape and terraforming and then adding the track, signals, key railway infrastructure like trackside equipment, and so forth. They'll also add all the relevant markers to the track so that the sim knows where [the] platforms are, where the stopping boards are on the platforms, and so forth. The amount of research required for this is enormous: Where are the signals? What types of signals are they? What are all the things they can tell the driver of the train? And so forth. Implementing a signalling system requires not just knowing "these signals go here" but how that system is intended to work in some detail.

Once the infrastructure team are done, it moves to the environment team, who have already been hard at work researching and making 3D assets for tunnel portals, bridges, and other key buildings that are on the route. Now that they have the track, they'll begin making all the stations and their platform layouts, a complex task since it's crucially important that the platforms are built and sized correctly, not just because of how they look but also because gaps that are too wide or too narrow will then cause problems for the player and non-player characters later on. Another part of this task is then setting up all the stations, defining where characters can walk, where entry and exit points are, where characters can sit, and so forth.

The last team to touch the route are the gameplay team as they come in and look at what fun things they can get the player doing, understanding how the trains really operate on the route and recreating the normal day-to-day operations. They'll also be looking at what exceptional operations might be possible and try to come up with some fun, interesting ideas to use in scenarios.

I'd say gathering all the audio has probably been one of the biggest challenges, with the team going off around the world to various locations, often multiple times (we had three recording trips for Flying Scotsman!). These trips are a lot of fun for the team, but they are also brutally hard work, often involving a lot of working through the night or very early morning.

Our engineering team has also had a massive challenge this year with the scale of the changes that were added, with new gameplay modes as well as enhancements across other areas of the game and trying to make something like Free Roam work with all our back catalogue as well throughout several years of different ways of making trains, they've had their work cut out making it all work smoothly and reliably for players.

We have spent a lot of time over the years working with players at all levels to understand where they find the fun, [and] what they find challenging-fun vs challenging-frustrating. Driving trains is a surprisingly difficult thing to do; I think a lot of people come into it expecting it to be "go" and "stop", but when you first sit at the controls and you see this sea of buttons, switches, and levers in front of you, multiple computer screens, many gauges, and such, you start to realise there's a lot more to it. Sometimes, these behaviours are not obvious at all, such as on a US freight train, where the brakes are potentially different at various points down the train because of how they work, you can be in a situation where you think your brakes are released, but they are still set on the last half of the train and not released yet. 

In the previous release, we added the Training Center to try and address some of the learning challenges of trying to get to grips with operating trains, and we took a lot of feedback from player experiences with this to rework and extend the training for Train Sim World 4, adding a range of new tutorials and new trains to learn on.

We have also extended our Driver Assist functionality in the sim because we often find that the best tutorials are still not much use to you when, a few hours later, the train will not move for some reason, and you can't figure out why. Driver Assist will now pop up and give you a hint, such as "the driver's door is open, which means you can't release the brakes."

It starts with hunting down as many photographs as possible online and arranging access with the operator where possible. We'll try and find as much data on the performance of the train as possible, including manuals (amazing what you can find online sometimes, particularly for older trains!). If possible, we'll try to talk to drivers and others who work with the trains and get their experiences on how a train drives and any quirks it has.

For our reference trip, if one can be arranged, we'll take an awful lot of photographs. Most of the photos we want are not the kind you see people sharing online; we want the grubby underside, the rooftops and all those fine close-up details that you really can't see well from the platform.

Our Train Setup team will spend a lot of time looking at the cab, recognising gauges and controls, and seeing what they can already understand versus what is new and perhaps not understood; this will then give them a start on where they need to spend extra time on research for this specific train.

The entire process is quite difficult for the team because of the inherent complexity and requirement to model something as close to reality as possible. However, I'd say that the most challenging area is certainly the underlying simulation implementation, how the electronics, air systems, and other aspects of the train work, what components are involved and how they interact with each other. As an example, we had one instance where it became clear that throughout an 8-car train, a "simple" application of the brakes resulted in different brake pressures being applied on each car in the train, something not covered in any of the documentation we had found nor understood by drivers.

This process is highly specialised and requires a very in-depth detailed knowledge of how trains work to both understand the data that's found and then figure out what's implied or missing from the documentation to complete the puzzle.

There's lots to explore across all the trains and routes.

In Flying Scotsman, aside from lots of interactive hatches and doors, you'll find the corridor connection in the tender can be crawled through with access into the adjoining coach, just like [in] reality.

In the Vectron, you'll find some of the most comprehensive and advanced simulations on an electric locomotive in the sim to date, including support for multiple countries overhead electric systems and some clever behaviours built into the way the traction motors work. [For Example], if you leave it at certain throttle settings for a while, it will start cutting traction motors out to save power and spread the load across other traction motors dynamically, all of which you can see happening on the computer screens, and all of which is actually being fully simulated down to the wheels on the rail.

There is an amazing new Passenger Information System on the Vorarlberg route that matches the real one, letting you see the trains coming through each station.

All the electric routes in Train Sim World 4 also now feature something called Neutral Sections, a real-world feature that is needed to support the power lines travelling over long distances. For the drivers of trains, it can mean different things to their journey depending on the train they're driving, but [it] is usually as simple as resetting the main circuit breaker. The most complex case, though, is travelling between Austria and Germany on Vorarlberg, where you must lower the pantograph, change the overhead power country setting on one of the computer screens, raise the pantograph, [and] and then reset the circuit breaker. [It's] great fun for players and exactly as per the real trains in that area.

For me, personally, it's been across the board. It's always fun seeing the development progress as the routes and trains come to life, but the new ways to enjoy that content have really set this release apart. Free Roam really does let you enjoy your collection in a new way, putting you in full control of what trains you drive, [and] where. This feature has developed and grown from early prototypes through to the version in the release through numerous iterations (and issues!), and that journey is always a lot of fun.

One of the aspects of Train Sim World 4 that I know our players are extremely excited about is the introduction of our first full editor. This is a Windows tool based on the Unreal Engine 4 editor, but with all our modifications and tools — all the same tools that we use internally to make the trains and routes that you're enjoying. This will empower the more advanced creators to potentially create anything they want in the sim.

These are advanced and complex tools to use, so they are not going to be useful to everyone, but ultimately, we will all benefit as a wider group of creators start making amazing trains and routes for us all to enjoy.

It's going to be exciting [to see] what directions the community take things, and I'm looking forward to seeing some unusual creations from a wide range of developers!