Making an extended trip to the UK, and I may need to travel with my larger 26" checked-in rollerbag instead of the usual smaller 21"-22" carry on. If I have only that one piece of 26" luggage, is it viable to travel the country, using the national railway system (will the trains have large enough luggage racks) and using the london subway?

Or should I bring two pieces of 21"-22" luggage instead? Thanks.