View as PDF - Rail Professional

Maintenance Comment
Steve Yianni, director of engineering for
Network Rail, says: ‘The real advantage of the
New Measurement Train is the speed with
which we can monitor and measure track
geometry. Traditional methods are much
slower, much more labour intensive.’
The NMT has also improved safety.
Prior to its introduction, track geometry was
tackled on a ‘react and repair’ basis, where
now Network Rail has been able to move to
a ‘predict and prevent’ maintenance regime.
The train, which began operations in
2003, records the level of contact between
the rails and wheels, as well as monitoring
the track gauge, twist and cant. A vibrating
platform checks for missing Pandrol clips,
used to attach rails to the sleepers. In 2009,
a pantograph was added to the top of the
NMT to record the height and stagger of
overhead lines. Video footage also records the
pantograph and wheel interfaces.
The NMT is formed of two HST power
cars, out of a pool of three, and a rake of
Mark 3 coaches that house banks of screens,
a mess car and conference facilities.
‘If you imagine the railway as a road, it’s
monitoring the quality and condition of that
road, and where there are variances from the
accepted norms it gives us the information
that we can feed to our local maintenance
delivery units to intervene. The parameters
are variable according to the speed of the
line,’ explains Yianni.
‘The whole process is quite slick, he
adds. ‘The NMT goes out and records track
information, which gets processed in Derby.
Then the information derived from the
data gets sent to the relevant maintenance
delivery unit. They then go to that specific
location and if there’s a geometry defect, they
go in and rectify it.’
The train-borne monitoring team as a
whole records 250,000 miles of infrastructure
every year.
‘The real advantage of
the New Measurement
Train is the speed with
which we can monitor
and measure track
geometry’
Using ultrasound to
monitor rails
The speed at which the NMT moves
limits the functions it can carry out.
The condition of railheads cannot
be accurately assessed at 125mph, so
slower trains do this instead using
ultrasonic technology.
‘There are lots of things that
we need to inspect,’ says Yianni, ‘It
would be great if the NMT could do
everything, but we’re limited by the
speed – the physics – of ultrasonic
waves, so we have a different fleet of
vehicles to do that for us. Cracking
and defects on the railhead are
checked by the ultrasonic train. It’s a
slower-moving train, typically going
at 30-40mph, and it has specialist
instrumentation on it to check
specialist information on the railhead.
‘When we find a defect, we verify
it locally with a hand tool. If it’s
confirmed as a crack, then we fix it.’
Giving off all the right Signals
• Mimic Panels
• Control Panels
• Fully Wired Location Cases
• FSPs (Functional Supply Points)
• DNO & Points Heating
• Fishplates
• Treadles
For all your engineering and signalling needs contact
Henry Williams on Tel. +44 (0) 1325 462722
Email. info@hwilliams.co.uk Web. www.hwilliams.co.uk
AUGUST 2010 PAGE 29