The route
This service runs the length of the West Coast Main Line, the historic trunk route connecting London to Scotland via Birmingham, the Lake District and the Scottish Borders. Avanti West Coast's fastest advertised timings sit around four and a half hours, but a normal midday departure with the usual intermediate stops is closer to five — worth checking the specific timetable entry rather than booking off the headline number.
The scenery earns its own mention on the northern half of the journey: the line climbs through Cumbria and crosses into Scotland with the Southern Uplands visible from the window well before Glasgow itself comes into view.
Why Glasgow, not just Edinburgh
Glasgow is Scotland's largest city by population, though Edinburgh is the capital — the two have distinct identities that get flattened together by visitors who only have time for one. Glasgow's character comes from its mercantile and industrial past: it grew rich on shipbuilding along the River Clyde, and that wealth built a city centre of confident Victorian and Edwardian architecture rather than Edinburgh's older medieval core.
The city is also the home turf of Charles Rennie Mackintosh, the architect and designer whose Art Nouveau style is stamped across several buildings still open to visit, and it has a livelier, less tourist-oriented arts and music scene than Edinburgh's festival-driven calendar. Glasgow Central station itself, a grand 1879 terminus with an enormous glazed roof, is worth a look upward before you leave the platform.
Pairing it with Edinburgh
The two cities are only about 45 minutes to an hour apart by train, so an itinerary that includes both doesn't cost much extra travel time — the real cost is budgeting for three separate city-stops (London, Glasgow, Edinburgh) rather than two, since neither city rewards a rushed half-day visit.
If the trip only has room for one Scottish stop, Edinburgh's density of famous sights within walking distance makes it the easier single visit; Glasgow rewards travellers who want a Scottish city without the tourist trail, and who have a full day or two to spend in it.