headlights
 

This applies to all modern trains.
What's the rule with marker lights on trains? Most trains are fitted symetricly (my spelling's not itself today) with a pair of white front marker lights, a pair of red rear marker lights, and in most cases, a pair of bright headlights. During the day when I do all my trainspotting, all trains seem to have both the marker lights on, but only the right hand headlight on. In fact, some earlier inner suburban trains are only fitted with a right hand headlight e.g: classes 313/4/5. but faster and more modern trains have one on either side. which brings me to ask: what are the rules about when to use which headlights?

(i'd prefer to have a brief answer rather than a link to some complicated page on rules)

Other than 'day headlight' being used during 'daylight hours' and 'night headlight' being used in 'night time hours' there is no rule as such. When I was driving for Thameslink, I was told to turn the night light on was when the street lights came on or it was 'obviously night time'. If there is only one headlight it must be used at all times when on the mainline. In sidings and depots, no headlight should be used, only the two marker lights.

Some trains don't have both marker lights on, I think trains built after, but not including, the 319/0s have just one marker light on, on the opposite side to the headlight in use.

Click here for a picture of 319/3 (319/1) with headlights on
Click here for a picture of 319/4 (319/0) with headlights on

Trains built now have to have a headlight in the roof above the cab on at all times.