The gameplay update is finally here! This update brings more goal-oriented gameplay mechanisms and several quality-of-life improvements.
Let's look at all the new features in this update:
The new career mode offers an alternative to the individual runs, providing more continuity and balance between player choice and randomisation. Pick any route and start with the easiest runs, working your way up to the more prestigious ones as you gain experience points from successfully completed runs.
A total of 21 achievements wait for unlocking. Some of them are meant to expose you to different styles of playing and experiencing the simulator, in ways that might not be immediately obvious.
Locomotives and powered units in the same formation that can't be multi-unit controlled from the leading vehicle now have tandem drivers.

The role of a tandem driver is to help accelerating the train whereas braking is still handled by the leading driver. You can choose to play as the tandem driver on services that have multiple drivers, otherwise they'll be operated by AI.
You can play as a goods train guard, operating the handbrake to keep the troublesome trucks in check.

The scoring system has been revised to be more accurate and easier to understand. New penalties have been added to encourage prototypical driving that minimises wear and tear. The HUD has a new helper option that shows penalties live during the run for instant feedback.
The game now supports one or more user profiles per Steam account. Statistics like miles driven and average score per train type are recorded for each profile. Old profiles will be imported automatically from the scoreboard of the old version.
Trains now derail when negotiating curves too fast. The derailment threshold speed depends on the curve radius and the length of the fixed wheelbase of the vehicle. Once the train has derailed the run ends and cannot be recovered.

Derailments can be enabled or disabled in the route editor per route. Old routes have derailments disabled by default as they may have sharp corners where the train would always derail, even when running within the speed limit.
It's now possible to layer different traffic patterns for a single run by selecting multiple timetables, for example, to create a mega busy timetable where nothing runs on time.
The new main menu system is more consistent, discoverable and easier to use than the old one. It's navigable with arrow keys and gamepad instead of being mouse only. The visual style is not final and will be improved in some other update in the future.
A simple top-down map view similar to other train sims has been added. The main purpose is to visualize the path for complex reversing manoeuvres that previously were explained in text only. The default key for accessing the map is 9. Hold down right mouse button and use WASDEQ keys or the mouse to zoom and move around.

Cab controls can now be operated with the mouse wheel and gamepad triggers. The operating principle of simple controls has been changed to be more intuitive: instead of selecting the target acceleration/deceleration, simple controls now set the target amount of power or brake directly.
The new HUD looks better and presents data in a clearer way. The visual style is not final and will be improved in some other update in the future.

The new menu system allows adding and removing vehicles using the "Edit formation" option before starting a run. Previously, in order to use a train from the Workshop, a whole new timetable had to be created for it.
Headbob has been upgraded with forwards and backwards motion to give an idea of how fast you're accelerating and braking.
Changing to a different view within the train now has a short transition, making it easier to understand which car and cab you are in. It's also possible to view any car in the train, keys defaulting to Home and End for moving to previous/next car.
All trains have automatically generated flange, jolt and derailment sounds for extra immersion.
Trains no longer telescope or disappear when colliding with each other or track end buffers. Depending on the speed, they'll either stop or derail instead.
The main menu has an option for accessing a list of learning material about signals and the operation of railcars. For now these are just Youtube links to real driver training videos.
This update has tons of bugfixes and performance improvements. For instance, the AI systems for pathfinding, signalling and driving have over 60 individual fixes to them.
The original roadmap for this update listed a number of features that have either been postponed or cancelled:
While the update has been under beta testing for several months, it's quite likely that the next couple of weeks will be spent patching leftover issues.
The route, train and timetable editors also have several usability problems and shortcomings that make modding more difficult than it needs to be. Before proceeding to the next major update (the train update, see the roadmap below) some improvements are necessary to keep the modders going. Improving the train editor in particular is a prerequisite for starting work on the next major update.
Three major updates remain:
Further updates like new routes and other countries to be announced later.
Questions, suggestions, feedback? Leave a comment below!