The Trainbots

The Trainbots are train-like Autobots.

Primes

 * Steam Prime
 * Chugging Prime

Medicals

 * Sparkshot
 * Socket

Weapon specialists

 * Piston Spark

Martial artists

 * Trax

Soldiers

 * Spiker
 * Railan

Engineering geniuses

 * The Greaser Diesels