Last Friday an impatient motorist overtook a waiting vehicle at a railway crossing and missed a moving train by just three metres.

The driver ignored flashing lights and warning bells at the Derwent Park crossing in Hobart.

The state-owned rail company's corporate relations manager, Polly McGee, said such irresponsible behaviour was demonstrated usually on a Friday between 3pm and 5pm.

``Near misses take place at least once a week,'' Ms McGee said.

Young people were found ``surfing'' on the rear wagons of trains in the  North-West in two separate instances in the past few days.

The first incident occurred when two youths were found riding in a train's wagon at 2.15pm on Friday in Burnie.

They were last seen running down the tracks, Ms McGee said.

Yesterday about 3.30am two young people were again found in a train's rear wagon.

Ms McGee said the driver of the train ``flagged down'' police patrolling the area who cleared the train after the youths fled along the tracks.

``We have zero tolerance for this behaviour,'' Ms McGee said.

``Trains are big; they're heavy and they can cause a lot of damage.

``We don't want our message reinforced by a fatality.''

She said too many problems occurred due to ``sheer impatience''.

``There's a clear correlation between the end of work on a Friday  and the occurrence of these incidents,'' she said.

  The actions caused ``fright and shock for TasRail's drivers''.