I have a Active Record model \"car\", I would like to change the name of this model to \"train\" without changing functionalities inside, that\'s only>
I would recommend the following:
Change manually the Active Record model class into Train
Make migration to change the database table name from cars to trains
Make good search to change references from Car to Train.
If you have constantly the need to change database table names, you might want to reconsider naming the tables more abstact way. Like in this case you could have table called vehicles and have the "type" field specifying the type (for instance: car or train).