So why is it painted yellow? This is Network Rail’s colour, chosen to look like no-one else’s livery and probably also because most of the “yellow plant” (rail-mounted kit for maintaining the track and wires) and engineering trains (essentially freight trains transporting ballast or track) need to be visible in the dark, because we rail engineers rarely have the luxury of being able to do construction work during the day!
But the yellow train I like to watch out for is an HST (that’s your average intercity-type passenger train to non-trainspotters) painted bright yellow and marked “New Measurement Train” on the side. This one train is a piece of technology that has revolutionised how we maintain the UK railway because it travels the whole passenger network over a regular cycle and measures the condition of the track and the overhead wires (are they in the right place and delivering the right amount of power?), saving thousands of hours of track inspection time.
I once saw it stopped on a platform at Leeds, so I had the chance to walk along and see inside: there's a lot of lasers and computers aboard, and a travelling meeting room in one carriage! But the main work that goes on is real-time monitoring: a team of experts watches the high quality images and dimensions measured, and trigger a spray paint line when a fault is spotted so that when a crew is sent out to rectify it, it's easier to find. Of course, the fault is always 100m or so back from the start of the paint line, because this is all happening while the train is travelling at 125mph...
The output from the wire measurements are good enough to design from, without sending people out to run “height and stagger” surveys. The mainlines are covered every 4 weeks, while the secondary routes are covered every 12 weeks.
Earlier this month I was lucky enough to spend an hour with a track maintenance engineer who talked me through the mysteries of the measurement train outputs. I am responsible for designing remedial works for several embankments which are thought to be at risk of slope movement, and I wanted to find out whether the track was being affected. Sure enough, one embankment clearly showed repetitive track faults in the same place as my inclinometers were indicating movement, with an adjacent section on a viaduct hardly moving at all from one reading to the next.
So that’s why I appreciate the track monitoring train and this week I set a new record: the yellow train sped past me while I was on a site walkover on the Midland Mainline near Luton on Thursday, then today my train to Edinburgh just about overtook it at Newcastle. On the other hand, when I was in the Netherlands last weekend, there were yellow trains everywhere – being the colour of all NS intercity services...
Earlier this month I was lucky enough to spend an hour with a track maintenance engineer who talked me through the mysteries of the measurement train outputs. I am responsible for designing remedial works for several embankments which are thought to be at risk of slope movement, and I wanted to find out whether the track was being affected. Sure enough, one embankment clearly showed repetitive track faults in the same place as my inclinometers were indicating movement, with an adjacent section on a viaduct hardly moving at all from one reading to the next.
So that’s why I appreciate the track monitoring train and this week I set a new record: the yellow train sped past me while I was on a site walkover on the Midland Mainline near Luton on Thursday, then today my train to Edinburgh just about overtook it at Newcastle. On the other hand, when I was in the Netherlands last weekend, there were yellow trains everywhere – being the colour of all NS intercity services...
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