Why do Railway photographers wear high viz jackets?

Went on the 40 trip over the Central Wales yesterday. Great day out but why
exactly to Railway Photographers feel the need to put high viz jackets on to
take pictures?

This includes people halfway up mountain sides, on brdiges and lineside.

I would say the worst are those who put their Network Rail jackets on and
storm off down the track at stations with their cameras.

Just because you work for the railway doesn't mean you can go tresspassing
on the track to take photos in your spare time!!!

Tim


.