Signalling on the Elizabeth line
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Signalling on the Elizabeth line

November 16, 2019


Crossrail is a very challenging project, it is
the most challenging thing I’ve ever done. If you think about Crossrail if you
look at it from 40,000 feet it’s essentially a state of the art tunnel
underneath London, joining to what originally were Victorian railways in
Great Eastern and Great Western. So there’s a big mishmash of
technologies on those on the base of those railways. Some of those
technologies date back to the 1950s there’s a system called AWS which is
what keeps the trains safe on Great Eastern and Great Western and then there’s an upgrade to that system called TPWS – Train Protection Warning System – which is brought in after some of the accidents we had in the 90s. So Crossrail has to
have the unenviable task of being future-proofed in terms of having the
latest technology and we’re buying that technology from people like Siemens and
Bombardier and they only ever sell the latest technology. We’re also trying to
make this railway last 100 years. It’s the first interoperable railway that we
have in the UK and it’s interoperable because we’ve chosen a technology our
ERTMS – European Rail Traffic Management System – to be the heart of the system
because it’s future proofed for the Great Eastern and Great Western railways
and also because it’s a modern safe system of separating trains. The
challenge of making a ERTMS work in the UK is that you have to make it
compatible with the legacy signalling systems I spoke about before AWS and TPWS but the real challenge has been making that system work as a metro
system through the tunnel so we’ve had to incorporate into that mix another
signalling system a third signalling system called CBTC which is
Communication Based Train Control developed by siemens and this system is
like I said would be what you’d see on any mass transit system it’s a
high-precision signalling system and it’s high precision in that it can
manage stopping distances incredibly accurately to align doors and it’s got
additional levels of safety and interfacing with things like tunnel
ventilation and timetabling and how the service can recover from problems that
happen Setro scenario. So you can see because
we’ve got a tunnel joining two legacy systems having to be future ready we’ve
had to have three signalling systems and that means we’ve got a very complicated
train that has to work over all of those systems seamlessly that’s what we’re
getting to now we’re doing the final transition testing we have 200 test
cases which we are working on completing successfully before we enter into
passenger running and we have what’s called a regression argument against the
software so that we don’t have to actually do regression testing to prove
the future builds of the software I’ve unraveled any of the code that those
test cases have proven already we’re in the endgame now of proving those
remaining test cases between now and 2020.

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