London should be about 200 miles away, and trains at the time were not incredibly fast, so how does Bates go to London "for the day"?
By the turn of the 20th century, steam passenger trains could reasonably do 70 MPH, some in the open expanses of the western US were already hitting 100 MPH. So it is within the realm of possibility to take a local train to York in about an hour, and an express to London in 3-3 1/2 hours, including one water stop. It would be a long day including the hike to and from the station, but if Bates took say a 6:00 AM from Downton, he could be in London by 11:00 AM, have 4-5 hours for his mischief and still be back in Downton by 10:00 PM.
It would be interesting to see actual train schedules from that time period.
Not only that, but the line that served along the Yorkshire to London route was I believe the LMS. Their fastest engines by the 1920's were the Royal Scot 4-6-0's, which could easily sustain eighty miles per hour with short bursts into the high nineties. Water-stops were eliminated by the LMS's use of water troughs for locomotives to draw up water along the trough as they moved along at speed.
I was aware of the water troughs (water pans in the US) but not sure how widely they were used. They were rather problematic as they could not be used when temperatures were below freezing (more of problem in the US than UK), could easily fowl from debris, and in an age before air conditioning, required the windows in the front several coaches to be closed to keep passengers from getting drenched.
In 2009 a steam train did the trip (York - London) in 4 hours and three minutes.
What do you think?