This mod is a version of the original mod which is not deprecated, original one was deprecated for no reason.

Here is the original version: https://mods.factorio.com/mod/fluidTrains

Original description:

Adds the ability for other mods to add locomotives that use fluids as fuels. Does not change anything about the game on it's own and completely relies on other mods to add in the actual locomotives.

For an example of a mod that adds fluid locomotives, take a look at Steam Trains and Diesel Trains.

Disclaimer
This mod is based on the Diesel Locomotive mod by evildogbot100 and FuryOfTheStars.