In Mulhouse, in southern Alsace, are two very nice museums for classic cars and classic trains. I absolutely loved the Collection Schlumpf with its more than 400 classic cars & classic race cars. Also, you can have a look at the currently fastest production vehicle, the Bugatti Veyron which makes a top speed of 431km/h! The whole collection is super cool! I’ve spent more than 3 hours walking round and taking in those superb cars.
Afterwards I made my way just a few minutes by car across the city to the other museum which shows classic train, mainly French classic trains though. Both are definitely worth a visit but if I had to choose, I would go for the cars!