1 hour, 10 minutes on the faster trains
There is not any direct rail connection between Belfast and France. You will need to travel via London, using ferry service. It will cost you $90 to travel from Belfast to London (ferry and train both), and another $117 to travel to Paris from London via train.
The Eurostar travels between London and Paris, and between London and Brussels. It does not travel between London and Geneva.
Around 2hr 20mins
No
Between 6h13m and 7h30m depending on service.
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.
The Eurostar travels between London and Paris, and between London and Brussels. It does not travel between Paris and Geneva.
Eurostar train from London to Brussels is 2h 01m, London to Bruges 3h 25m
Journey by Train, Because I love train journey.
You can't take a train directly from the Shetland Islands to London. You can't even fly directly between Shetland and London. You could travel by boat from Shetland to Aberdeen and then take a train or fly from there to London or you could fly from Shetland to Edinburgh and either fly or take a train from Edinburgh to London.
train
Drive or take the train.