In short, the company hosting the commuter train service in Stockholm, Sweden, has decided to remove “train hosts” (tågvärdar), personnel responsible for comfort and safety of passengers, replaced them with cameras — a decision made by regional politicians — and put their responsibilities on the drivers. The drivers are now the single responsible person onboard, for up to 1800 passengers, in case of accidents, and persons who need assistance in their travel can no longer spontaneously travel but must book their travel in advance. This fight — that has been going on for 2 years — has been abandoned by the unions, and the drivers themselves now demand the return of the train hosts, hence the wildcat strike. The strike is planned to continue through Wednesday.
Information about the strike from the strike committee, and ways to support the strike, can be found here (Swedish): https://vildstrejkpendeln.blogg.se/
Best of luck to the striking drivers.