Amstellina

Downton Abbey is set in the 1910s-1920s, in Yorkshire (though not actually filmed there), and a return journey to London in the same day would have been possible in that era. The exact location of Downton is not given in the series but it is implied to be close to York, and therefore it would be easy to access East Coast Main Line services to London with a journey time of 3-4hrs on a steam-hauled train. That's a bit of a long haul for a day trip but it was certainly do-able. Today's electric hauled trains manage the same journey in just 2 hours - and there are more frequent services. Percyqted says "Overall journey times were just as fast in the late 1800's as the are now, quicker in some instances." That's completely untrue in Britain, as you will see by comparing any timetable from back then to a modern equivalent. Today's York-London electric trains routinely run at speeds of up to 125mph, which would have been a completely impossible speed for a 1890s-1920s steam train. Please check my blog here.