Retractable steps are standard on modern Swedish trains. This one slides out from under the floor. This probably pays for itself because people get on and off quicker and it presumably prevents accidents.
That is not standard on all trains, I have only seen it on the Regina trains which are normally quite slow.
They are also on the X31 Öresundståg and the X40 double deckers. Some version of the Regina is suppossed to replace the X2000 eventually which would be a pity and a bit of a waste because they could obviously continue in service for another 30 years, and the 1980s hauled stock is good for many more years.