replace with new type vehicle

[MoonKid]

Auto-replacement of old vehicels only work when the same type is avaiable. If it is not and only a new generation of that vehicel is available it doesn't work.

Can this be done somehow?

I don't want to replace old vehicles manually.

[planetmaker]

There is autorenew (replacing a vehicle with an identical model) and autoreplace (replacing vehicles with a different model). Both can be done. Check the wiki:

https://wiki.openttd.org/Replace_vehicles
https://wiki.openttd.org/Autorenew#Autorenew

Honestly, these two settings should simply be moved to the same place in the GUI, probably where there is the autoreplace now

[MoonKid]

This "autoreplace" isn't auto at all. I have to start it manually.

[planetmaker]

How would the game know with which vehicle model to replace your old ones, if you don't tell it? So, yes, sure, you have to tell the game once that you want it to replace your old models with another one. Once you set it, it will replace all your old vehicles with the chosen type - provided those vehicles can find a way to a depot to perform that action

[mak]

Just to add, in the drop down (arrow) where is says 'start replacing' you can select only old vehicles, this will replace vehicles over a longer period if you did not buy them at same time, so spreading cost.

[trainrover]

Mind, some newGRF vehicle fleets are not compatible with others, such that a whole rigmarole of guarding your depots becomes necessary when swapping your loco-hauled rake of coaches and mail cars for multiple units, such that de- and re-activating the replacement counterparts must be scrutinised awfully timely with immediately resending your trains back into the depot(s) upon 'flipping' those autoreplacement switches...does become altogether absurd by the fussiest of orchestrations, ARRRGGG