Werrington (ECML) diveunder could have been done better

[The Foghorn]

May I suggest that the Werrington dive under could have been done better.

If the down fast, up fast and up slow had gone down into a subterranean box, a junction with the Spalding line could have got trains over the top without conflicting with the main lines.

Add to this an extra left-hand turnout from the up slow before the dive under to then also cross the box to join the Stamford lines, and you would also remove the need for Liverpool - Norwich services to cross over at Spital Bridge Jn.

 

[yoyothehobo]

The line speed on the fasts at the Werrington are 125mph on the fasts. This means you would need an absolutely massive "box" with which to get the gradients in, also a 3 line wide box would be very expensive.

Groundwater conditions in the area were also very difficult making construction even more difficult than it already was.

You would also struggle to construct such a box without massive disruption to the ECML for an extended period.

 

[Magdalia]

Here is how the Werrington tunnel was built:

Werrington Tunnel: 'UK first' underground freight route opens

Network Rail says the £200m tunnel for freight near Peterborough will improve journey times.

www.bbc.co.uk

A £200m railway tunnel dubbed a "UK engineering first" has been officially opened by the rail minister.

The Werrington Tunnel was created by "pushing" an 11,000-tonne concrete curve under the East Coast Main Line (ECML) near Peterborough.

The "dive-under" system is designed to take freight traffic off the passenger routes - and took a year to build.

The same construction technique could not have been used if the box had needed to contain 3 ECML tracks.

 

[zwk500]

May I suggest that the Werrington dive under could have been done better.

If the down fast, up fast and up slow had gone down into a subterranean box, a junction with the Spalding line could have got trains over the top without conflicting with the main lines.

Add to this an extra left-hand turnout from the up slow before the dive under to then also cross the box to join the Stamford lines, and you would also remove the need for Liverpool - Norwich services to cross over at Spital Bridge Jn.

That's all very well, but 1. How much extra would all of this cost, 2. How much more disruptive would it have been to do, and 3. how much extra benefit would it have got?

The Liverpool-Norwich cross is 1 movement per hour in 1 direction, of a reasonably short unit. The bigger issue is the need for freight trains into/out of Peterborough yard to/from Stamford or Ely to still use the flat crossings. To that end the change I would make would be a new grade-separated movement from Up Stamford to Up Slow at Helpston Jn, and to make the Up Slow bi-di between there and Peterbrough so Down freight from the Yard doesn't have to cross the fasts.
If possible, squeezing in a tight curve from the Up Slow to the Up March just south of the station would then mean that only 1 freight movement was required to cross the fasts on the flat (Down Ely to the yard), although I'd retain the junction themselves for flexibility.

 

[Magdalia]

To that end the change I would make would be a new grade-separated movement from Up Stamford to Up Slow at Helpston Jn, and to make the Up Slow bi-di between there and Peterbrough so Down freight from the Yard doesn't have to cross the fasts.
If possible, squeezing in a tight curve from the Up Slow to the Up March just south of the station would then mean that only 1 freight movement was required to cross the fasts on the flat (Down Ely to the yard), although I'd retain the junction themselves for flexibility.

That's all very well, but 1. How much extra would all of this cost, 2. How much more disruptive would it have been to do, and 3. how much extra benefit would it have got?

Which trains do you have in mind that need to get between the Stamford lines and the yards at Peterborough? Most freight on the Stamford lines runs through to/from the March line and passes under the ECML near the bridges over the River Nene. The up slow is already bi-directional between Peterborough station and Werrington, for passenger trains departing the up side at Peterborough and going towards Spalding.

The proposed curve from the up slow, south of the station, onto the March line has no feasible alignment and also requires a very expensive bridge over the River Nene. There is a significant height difference between the two existing rail bridges over the river, as anyone who has walked to the Nene Valley Railway's station will know.

If we are worrying about remaining at grade conflicting moves across the ECML at Peterborough then highest priority are the morning peak ECS moves out of Nene sidings.

 

[jamieP]

Which trains do you have in mind that need to get between the Stamford lines and the yards at Peterborough? Most freight on the Stamford lines runs through to/from the March line and passes under the ECML near the bridges over the River Nene. The up slow is already bi-directional between Peterborough station and Werrington, for passenger trains departing the up side at Peterborough and going towards Spalding.

The proposed curve from the up slow, south of the station, onto the March line has no feasible alignment and also requires a very expensive bridge over the River Nene. There is a significant height difference between the two existing rail bridges over the river, as anyone who has walked to the Nene Valley Railway's station will know.

If we are worrying about remaining at grade conflicting moves across the ECML at Peterborough then highest priority are the morning peak ECS moves out of Nene sidings.

Still get a freights running across the junctions at Spital and New England Nth Jn to access the GBRf depot. Not much can be done about them all the ECS from the Nene without completely rebuilding the railway at and around Peterborough. The Werrington diverunder does what it was built for.

 

[The Foghorn]

And to be fair, it does it very well.