ERTMS - let's get on with it

[Philip Phlopp]

What advantage does ERTMS have over AWS and TRWS equipped conventional 3 or 4 aspect signals coupled with the mark one eyeball?

It's optimum signal section location, when you don't have to worry about where to put a light-on-a-stick.

It makes electrification much easier too, when you don't have to worry about enormous signal gantries with all the protection needed to stop the S&T techs shorting out the OLE with their bodies (seriously ERTMS is much safer on electrified routes) or having to use twin track or portal structures because a mast will interfere with signal sighting.

When we wire up a number of secondary routes, there's not likely to be a significant difference in cost between immunisation/moving signals about, fitting new signal gantries, posts and protection grids, versus sticking posts, heads and gantries into a skip and refitting the entire route with signal post free ERTMS equipment.

There's also the hope that with other European nations involved, we might get a signalling solution that's more reliable than the current equipment, which if we're being honest, does leave a lot to be desired at times.

I do dream of a world where signalling issues are counted per year, not per minute on some routes.

 

[Railsigns]

What advantage does ERTMS have over AWS and TRWS equipped conventional 3 or 4 aspect signals coupled with the mark one eyeball?

Off the top of my head:

• An ability to define signalling sections unconstrained by signal spacing and signal sighting considerations, maximising headway potential.
  
• Allows running at speeds in excess of 125 mph, subject to suitable track.
  
• Eliminates the need for expensive signal structures and OLE alterations to achieve signal sighting.
  
• Gives a better degree of train protection than that offered by AWS and TPWS.
  
• Less equipment on the ground means reduced maintenance costs.

 

[Bald Rick]

Let's take some routes as an example.
Victoria to Brighton.
Liverpool Street to Cambridge.
Birmingham to Bristol.
Leeds to Hull.
There are no worthwhile track improvements that can be made to speed these routes up from the existing line speeds. The only way would be faster accelerating and braking trains. What advantage does ERTMS have over AWS and TRWS equipped conventional 3 or 4 aspect signals coupled with the mark one eyeball?

It removes all speed restrictions caused by signalling, including approach controlled junctions, and 'blanket' restrictions where layout complexity requires all routes to have the speed of the slowest (eg Liverpool St).

It also removes a significant amount of kit from the lineside; less to maintain (so it is cheaper) and less to go wrong.

And it enables ATO, which does enable a small increment in capacity in some cases.

 

[DerekC]

Off the top of my head:

• An ability to define signalling sections unconstrained by signal spacing and signal sighting considerations, maximising headway potential.
  
• Allows running at speeds in excess of 125 mph, subject to suitable track.
  
• Eliminates the need for expensive signal structures and OLE alterations to achieve signal sighting.
  
• Gives a better degree of train protection than that offered by AWS and TPWS.
  
• Less equipment on the ground means reduced maintenance costs.

Lots of interesting stuff in the thread already. I think Railsigns is right on the button with the benefits, plus Bald Rick's additions. The only thing I can add to them is that the signalling design does not have to be constrained by the worst case train braking performance - or conversely (where it hasn't been) freight can run at passenger speeds if it has sufficient oomph.

And ATO has very significant capacity benefits, primarily because of the improvement in platform reoccupation time.

Having said all that, whoever suggested that ERTMS isn't a magic bullet for capacity is absolutely right. The way to look at it is how LU uses CBTC. A complete upgrade consists of CBTC plus better performing trains, better operation to reduce dwell times, more traction power, selective grade separation at junctions and (if necessary) extra terminal platforms. Not a cheap deal! However building more tracks is incredibly expensive (£3Bn estimate for one extra track between Surbiton and Clapham Jnc) so if we want to get more out of what we have got, that's the way to do it.

 

[OwlMan]

There is a Network rail website

http://ertmsonline.com/

 

[QueensCurve]

Given the shortage of signal engineers it would be no surprise if the programme slipped to the right.

That is the elephant on the track.