It varies on the time of travel and how far you book in advance. Expect to pay around £50 return for 1 adult, however you can get a substantially cheaper fare if you book between 10-12 weeks in advance.
London Edinburgh takes between 4 and 5 hours dependent on the stops.
Kings Cross Station
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.
About 7 hours
4 hours 30 minuites
About 4 hours.
Edinburgh is just under 400 miles from London. Fast train services from London's King's Cross station take around 4 hours to reach Edinburgh.
By time: 4.25 hrs to 4.75 hrs by train from London Euston to Glasgow Central.4.25hrs to 5 hrs, most are around 4.5hrs by train from London Kings Cross to Edinburgh WaverleyDistance: Glasgow - London (via West Coast): 403 milesEdinburgh - London (via East Coast): 393 miles
You will have to change trains in Edinburgh
About 4 hours 30 minutes.
The last normal train from Waverley is at 1900 but there is a sleeper that leaves at 2340.
Dublin is on the island of Ireland, so it isn't possible to take a train all the way from London. However, you could take a train from London to Holyhead and take a ferry from there but its so much easier and quicker to fly.