RAILWORKS сообщество

Ah, this old chestnut again.

Not all trains have a day/night beam, even where it appears that there is a headlight housing both sides. As I've said on previous ocassions, Cl317/6's have just the one headlight on the driver's side and, until recently, the headlight housing on the secondman's side was empty. These have since been wired up but only for use as an emergency headlight should the main one fail.

However, where a train has both a day and night beam the difference is in how they are set to throw the light. The day beam will shine across the track at the cess so that it is visible to trackworkers but doesn't dazzle drivers coming the other way. The night beam shines along the cess directly in front of the train to pick out reflective signs and other lineside features. In most cases a train will only show one headlight at a time, the only exception I'm aware of (on the NR network at least) are Cl91's and Mk4 DVT's which show both headlights.

Just to correct a couple of other points. Not all trains have LED marker or tail lights, as many still have filament bulbs. Likewise the modern standard for headlights is to use HID bulbs rather than halogens. These are MUCH brighter and have that "cool blue" light.

To come back to the original question, the point of having headlights on all the time is twofold. Firstly it makes an approaching train more visible to anyone on or near the line. The sooner you see a train the faster you can move to a position of safety. Secondly it shows which direction the train is travelling. Again there are one or two rare exceptions in the Rules, but generally speaking white lights means a train is heading towards you while red lights means it's heading away from you.

O L Leigh