Train Sim World 7 Continues to Rely on Unreal Engine 4 – How Much Longer Can Dovetail Expand This Foundation?

We asked ourselves almost exactly this question at Simulatoren-News a year ago. In September 2025, the topic was why Train Sim World 6 still relied on Unreal Engine 4 even though Unreal Engine 5 had long been available. At the time, there was a fairly significant reason that no longer exists today: Train Sim World still had to support PlayStation 4 and Xbox One.

Since August 2026, the situation has changed. Dovetail Games is now developing new Train Sim World titles and new add-ons only for PlayStation 5, Xbox Series X|S and PC. New content is no longer being developed for PS4 and Xbox One. Dovetail explicitly justifies this step by saying that it will allow current hardware to be used more effectively, performance to be prioritized and visual quality to be improved further. Previously released older content will remain available on the existing platforms.

This removes precisely one of the arguments that still seemed particularly obvious a year ago.

The old consoles are no longer holding back new Train Sim World content. Unreal Engine 4 remains, nonetheless.

That does not mean, however, that Train Sim World 7 is simply standing still technically. Quite the opposite: Dovetail is now getting significantly more out of the existing foundation.

On PC, TSW7 will use DirectX 12by default in the future. In addition, there is DLSS 4.5 with DLAA and upscaling, as well as FSR 4 with upscaling and frame generation. A new “Epic” graphics profile is intended to enable greater view distances, larger LOD distances and shadows extending farther into the distance. At the same time, the lighting system has been revised further. Among other things, Dovetail mentions sharper shadows extending farther into the distance, improved bloom and light rays, as well as a more natural-looking representation of the sky.

This is important for putting the situation into perspective: An old engine version does not automatically mean that a game can no longer receive modern graphics technology.

Train Sim World 7 is actually a pretty good example of this. Dovetail is expanding the existing technical foundation with features that many players would normally associate more with modern games. Anyone merely looking at a screenshot therefore will not automatically be able to say: “That must be Unreal Engine 4.”

And that may also be the reason why Dovetail has so far been able to avoid making a major break.

Train Sim World has long been more than just a base game with three routes. It now has a huge ecosystem of routes, locomotives, timetables, layers, scenarios, third-party developers and older content that some players have owned for years.

The August roadmap for Train Sim World 7 alone lists more than 20 upcoming or still-in-development add-ons and projects. These include the Tadami Line, Neckartalbahn, Rhein-Niers-Bahn, Lisbon–Setúbal, Amsterdam–The Hague, London King's Cross, a new Romanian route, the ÖBB Railjet, DB BR 212 and numerous other vehicles and expansions.

And Train Sim World 7 is not intended to simply cut off this existing system.

Dovetail is once again offering a free Starter Edition that allows existing players to move to the new generation and then continue using their collection. This continuity has by now become a central part of the TSW model.

That is convenient for players – technically, however, this very strength could eventually also become a problem.

Because the larger the library becomes, the greater the responsibility to keep older content running. A route from a much earlier Train Sim World generation is supposed to work alongside a brand-new TSW7 DLC. Vehicles are supposed to appear in new timetables. Layers access other DLCs. Route Hopping now even connects different routes with one another.

The system is therefore not only growing outward, but is becoming increasingly interconnected.

And that is precisely what makes a possible engine switch more complicated.

A jump to Unreal Engine 5 would not simply be a switch that suddenly activated Lumen, Nanite and perfect performance everywhere. Train Sim World has numerous proprietary systems and technologies that have been developed and adapted for railway simulation over many years. This includes Dovetail’s own SimuGraph system for vehicle simulation.

The amount of existing content makes things even more difficult. Older routes, vehicles, materials, lighting, timetables and third-party projects would still have to work or be adapted accordingly. Even with much smaller changes, it repeatedly becomes clear that maintaining older content is not trivial. For example, when asked in June about adding features retrospectively to older content, Dovetail explicitly explained that such changes are often not a quick intervention.

This makes the current situation almost paradoxical.

The more successful Train Sim World becomes with its existing structure, and the more DLCs are released, the more difficult a radical technical restart could eventually become.

Waiting another year does not merely mean another year of older technology. At the same time, it means another year of new routes, vehicles and systems that would have to be taken into account in a later transition.

On the other hand, Train Sim World 7 is currently showing why Dovetail does not necessarily have to take this step immediately.

DirectX 12, DLSS, FSR, greater view distances and improved lighting address some of the areas in which players can actually see or feel technical progress. Even on the existing architecture, Dovetail can therefore still implement improvements. This makes TSW7 more of an evolution of the existing technology than a restart. That is also how developer Jetwash, who was involved in the lighting improvements, describes the graphical development: evolution rather than revolution.

And, fittingly, Dovetail is now making another major break when it comes to performance: the old consoles are disappearing from future development.

For the first time, this gives the developers significantly more room to maneuver without having to take hardware from the PS4 and Xbox One generation into consideration at the same time.

In theory, this could allow Train Sim World to continue living on its existing foundation for several more years.

But the long-term question does not disappear as a result.

Because while Dovetail continues to optimize the UE4-based technology, the rest of the games industry is moving forward. New rendering techniques, streaming systems and development tools are emerging. At the same time, players’ expectations regarding view distance, vegetation, large stations, traffic density, lighting and performance are increasing.

Train Sim World 7 in particular now makes this contrast especially visible: On the one hand, Dovetail is promising a graphics profile above Ultra for the first time, greater view distances and less visible pop-in. On the other hand, this still requires a technical foundation whose origins lie many years in the past to be expanded further and further.

And it is precisely in 2026 that this question is becoming more interesting than it was in our first article.

At the time, one could say:

“UE5 would be nice – but TSW still has to run on PS4 and Xbox One, after all.”

That argument is now gone.

The new question is therefore no longer exclusively why Dovetail has not switched yet.

It is:

How much longer is it worthwhile to keep putting increasingly modern technology on the existing foundation – and at what point would a genuine new beginning be easier in the long term than the next expansion?

Train Sim World 7 shows both sides of this problem at the same time. Dovetail proves that Unreal Engine 4 does not mean that nothing technically new is possible anymore. DirectX 12, upscaling, frame generation, greater view distances and new lighting systems demonstrate this quite clearly.

But every new DLC, every additional third-party developer and every further connection between existing routes also makes Train Sim World larger at the same time.

At some point, the enormous collection that is currently one of Train Sim World’s greatest strengths could therefore become the most difficult part of a technical generational transition.

What would be more important to you: that Dovetail keep all existing DLCs compatible for as long as possible and continue improving Unreal Engine 4 – or would you eventually accept a genuine technical restart with Unreal Engine 5? Would you even be willing to accept that not every old route comes along immediately? And are the improvements in Train Sim World 7 sufficient for you for now?