Some train stations will also have a secure (attended) baggage storage, although I don't know if anything has changed in the last few decades. But, it is possible that if all else fails, you could just drop off the bikes at the train station, and carry your bags wherever you're headed.

I managed to take my bike on the trains twice (alone). Once was about 50 miles on some kind of a bi-level commuter train north of Venice. I just hung around near the entry way, and nobody noticed.

The second time was between Verona and Modena with the standard compartment cars. I had the bike compacted down, but no cover. It wasn't bothering anybody, however, the train conductor decided I couldn't have it, and kicked me out of the train in a small town in the middle of nowhere, at midnight, last train of the night. Fortunately, I had a bike

Anyway, if you do decide to take bikes on the train, either check them in the baggage car if you can, or if you take them as luggage, make sure they look like luggage.