Rail passengers say they have been travelling on "very full" trains with no social distancing over the weekend.
East Midlands Railway (EMR) users say passengers have been standing in the aisles, with too few carriages available to accommodate them spread out.
One passenger tells the BBC: "It seems a bit farcical. It's a bank holiday - they knew it was going to be busy."
EMR has apologised for "the discomfort and inconvenience that some of our customers have experienced".
Current government guidance says although close contact with friends and family is now a personal choice, it advises people to "maintain social distancing" on public transport, as well as in the workplace, in businesses and at public venues.