Between 6h13m and 7h30m depending on service.
You can not travel by train from CA to London. There is an ocean between the two.
You can't travel directly from Heathrow to Bristol. The best way is probably to take a bus to Reading and get a train from there or travel into Central London and get a train there.
About 4 hours
about 20 h
About two days
About 35 minutes.
About 2.5 hours
There are no trains from Minnesota to London, England. Train travel is not possible across the Atlantic ocean.
You can't travel directly from Amsterdam to London by ferry because London doesn't have a ferry port. You would have to travel from Amsterdam to Hook of Holland by train (or drive), catch a ferry to Harwich and then take a train (or drive) to London.
I suppose that 50 hours is sufficient.
About 1 hour 30 minutes by train.
Malta is an island in the Mediterranean Sea so you can't travel there by train from anywhere.