Boat train


I know there was the Boat Train, but that seems to go as far as London. How would (especially a third class passenger) get from home (especially in Sweden) to Southampton to board the boat? Would they take a train the whole way? Obviously they weren't walking or driving, that's the only option I could think of.

Thanks for your help!
I understand that there were actually two Boat Trains from London, the first carrying Second and Third Class passengers, the second for First Class exclusively. To get from Sweden in the first place, I would think that Second or Third Class passengers would have taken a steamer from there to England, perhaps London, and stayed there until ready to depart for Southampton.
I would think that many passengers from the other European Countries took a steamer to Southampton, and waited until April 10th, when they boarded TITANIC.
I would suggest that travellers from Scandinavia or north-western Europe would have made their way to the Hook of Holland and caught a fast Great Eastern Railway cross-channel steamer to Harwich, from where the GER ran trains to and from London (Liverpool Street). They would then have crossed London (via the Underground Railway) to Waterloo, and boarded a London & South Western Railway train to Southampton. Alternatively, they might have boarded the White Star vessel at Cherbourg, thereby obviating the need to cross England from east-to-west.
Passengers from Sweden mostly went by steamer (generally the Wilson Line) to the port of Hull in East Yorkshire, and from there traveled on the Great Northern Railway to King's Cross Station in London, thence to Southampton over the route that Stanley has described.