I've gone completely back and forth on this in the last couple of hours. At first I wasn't too thrilled, as I don't really find trains that cool. I can't really imagine train-themed Sentai helmets working well, and a mecha forming from trains just seems like a very boring five rectangular blocks become torso, arms and legs type combiner.
Then I remembered a few things:
1. If I'd been in the fandom 7 years ago I'd have been equally apprehensive about a train-themed Kamen Rider, and yet Den-O is one of my top three Rider series.
2. Just as 'Tokumei Sentai Go-Busters' gave us no clue the characters' helmets would be based on a cheetah, a gorilla, a rabbit and a pair of beetles, and 'Ninpuu Sentai Hurricaneger' gives us no clue that it would be arming its' characters with a blow-dryer, a megaphone and a mallet, the name of this series doesn't give us any clue what other gimmicks they'll include to add more interest.
3. I may not be into trains now, but when I was 2 or 3 years old, I was massively into the Thomas the Tank Engine books and TV show and had a big collection of toy engines. On the same principle, I can imagine a train Sentai being really popular with the little kids watching.
It seems like Kyoryuger is flying past, and I'm enjoying it enough that I can't say I'm looking forward to a time when it's not around, but that just means that a 'Vehement Kyoryujin' combination is on the way!!!