What can be more of a problem is buying a train ticket if you have a loaded touring bike with you.
If you have a companion, no problem: one minds the bikes while the other buys the tickets.
If you're on your own, you have a problem.
At many stations, you'll be hustled out of the ticket office if you take your bike in with you, as it's "a hazard". Why it's a hazard in a spacious, well-lit ticket office but becomes miraculously harmless on a crowded, swaying, ill-lit train with people climbing over it every five minutes is a mystery. Also, why is a bike so dangerous in a ticket office when wheelchairs and armchair-sized wheely suitcases (usually operated by careless drivers) apparently aren't?
But if you leave it anywhere outside, it becomes "unaccompanied baggage" and you're likely to find the Transport Police have taken it away.
The only solution appears to be to remove all the bags, lock up the naked bike and carry all the bags into the ticket office. Of course, by the time you've done this, you'll have missed the train.
Like Mike1026, I once found a railway employee who promised faithfully to keep an eye on my bike while I bought a ticket. When I emerged, he was nowhere to be seen. Thanks, mate.