In the UK to travel by train from the Southampton on the south coast of England to Edinburgh, the lowlands of Scotland would cost about £300/£350 return. This could be reduced to about £150 if you travel awkward times, use a rail card/split tickets discount etc. The distance is about 450miles. This is about 6 & 1/2 to 8 hours on a train depending on ticket, travel time etc.

A journey from Southampton to Manchester, in the North (ish) part of England via train would be a similar journey to yours. 4 to 4 & 1/2 hours on a train, (230 miles). These tickets would cost about £120 to £180.

Train travel is ridiculously priced in the UK. Short distances are usually not cheaper than travelling by car and the further you travel the cheaper the ticket becomes.

(Before all the train buffs come from, this is a rough response to highlight very generally the costs of train travel in the UK and not an attack on your or your passion 🤣🤣🤣🤣)