From OpenTTD

Contents 1 Manual replace 2 Autoreplace 2.1 Wagon removal 2.2 Funding 2.3 Servicing

[edit] Manual replace

You can replace a single vehicle without losing its order list following these steps:

1. send the intended vehicle to a depot
2. delete (sell) the vehicle (or the engine only if it's a train)
   • now, the first new engine/vehicle built will have the same order list of the just deleted engine
3. build the vehicle/engine of the desired type (it will have the same order list of just deleted one)

[edit] Autoreplace

Autoreplace is a helpful feature implemented by Bjarni which allows you to upgrade your entire fleet of a certain kind of vehicle to a different type without having to sell and replace them individually. Imagine you've just finished building up a network of 40 buses and then a new bus type arives - it would take a significant amount of time and effort to send all those to depots, sell them, and then buy the new bus - this is the kind of situation where you need autoreplace. You can replace train models to another train model, and wagons can also be changed. This is most helpful in NewGRF sets which introduce new, faster wagon types as the game progresses.

To get to the replace vehicles screen, first open the vehicle listing of the type of vehicle you want to replace (trains are shown in the screenshot below). Then from the Manage list menu, click Replace vehicles.

The replace (vehicle type) window appears, which looks like the one for trains below.

The left hand pane shows the vehicles you are currently using. The right pane shows new vehicles available for you to upgrade to. You click on the old and new types to select them define the replacement.

If you are upgrading trains, there are several types available, and you can choose the type by adjusting the menu at the bottom in the middle of the window (displaying Electrified Rail Vehicles above). For trains you may also toggle between replacing engines and wagons by clicking the Replacing: Engines button shown.

Naturally it is not possible to upgrade between different types of train because the train would need to be able to enter a depot and leave as a new type. The exception to this rule is upgrading from normal to electric trains (if you have electrified rails in place) since both will run on electrified rails and can be built from electrified depots.

To begin replacing vehicles once you have made a selection, you click Start Replacing Vehicles.

Once all vehicles of a type have been replaced, the old vehicle type will turn grey in the replace vehicles window (as the Floss 47 is showing above). Click on it and click Stop Replacing Vehicles to complete the procedure and it will then disappear from the list.

[edit] Wagon removal

In the bottom-right corner of the replace vehicles window is a button labelled Wagon removal on/off. If this option is set to on, then when a 1-unit engine (for example, the Gresley A4) is replaced with a 2-unit engine (the IC125 for example), the first carriage in the train will be sold to maintain the original length of the train.

Note that this only works one way; if you were to replace a train with two engines (e.g. IC125 or some DMUs) with a single engined train, you would shorten the overall length. It is not padded back up to the original length because you cannot specify which carriage would be used to do that.

[edit] Funding

OpenTTD will only replace vehicles if you have sufficient funds, to avoid wasting money on upgrades that would be better spent on new routes. If you have less money than the Autorenew money then when a vehicles enters a depot for its service, you will get an error.

[edit] Servicing

Your vehicles will not all be sent to depots for replacement as soon as you click Start Replacing Vehicles. Instead, they will be replaced when they are next serviced or replaced by autorenew.

Of course, if you have Disable servicing when breakdowns set to none on and breakdowns off, your vehicles will not go to a depot and therefore will not be replaced.