The Anonymous Widower

Digital Signalling Work Outlined By Network Rail For Northern City Line

The title of this post, is the same as that of this article on Rail Business Daily.

This is the first paragraph.

Network Rail has detailed work due to be delivered on the Northern City Line to Moorgate.

I use this line regularly and I believe that with digital signalling the Northern City Line could see a large increase in frequency.

Currently, the service from Moorgate is as follows.

  • 4 tph to Welwyn Garden City via Potters Bar
  • 4 tph to Hertford North of which 2 tph extending to Watton-at-Stone and 1tph of those continuing to Stevenage.


  1. tph is trains per hour.
  2. Although the service is reduced from that shown, because of the pandemic and lower passenger demand.

But eight tph means a train every seven minutes and thirty seconds.

If you look at London’s high frequency lines, they have or will have passenger frequencies as follows.

  • Crossrail – 24 tph on dedicated tracks with digital signalling.
  • East London Line – 16 tph on dedicated tracks.
  • North London Line – 8 tph on tracks shared with freight trains.
  • Thameslink – 24 tph on dedicated tracks with digital signalling.


  1. The East London Line is planned to go to 20 tph with two extra tph to Clapham Junction and Crystal Palace.
  2. 20 tph means a headway between trains of three minutes.
  3. 24 tph means a headway between trains of two minutes and thirty seconds.

It should also be noted that the Victoria Line runs upwards of thirty tph on a fully digitally-signalled line.

What Level Of Service Would Be Possible?

These are my thoughts on various aspects of the Northern City Line.

How Many Trains Could Be Handled Between Finsbury Park And Moorgate?

This section of track is a simple double-track with a diamond crossing to the North of the two platforms at Moorgate, so that trains can use either platform.

This layout is used at Brixton and Walthamstow Central on the Victoria Line and Battersea Power Station on the Northern Line to name just three of many.

So I suspect that the track layout at the terminus at Moorgate can handle well-upwards of twenty tph.

The new Class 717 trains that run into Moorgate have an operating speed of 85 mph, which is faster than the previous Class 313 trains, which appear to have run at 30 mph South of Drayton Park.

I suspect that eventually twenty or even twenty-four tph will be possible on a digitally-signalled route between Finsbury Park and Moorgate.

But in the interim, sixteen tph would be a good compromise.

How Many Trains Could Be Handled On The Current Routes?

Currently, four tph use the both the Welwyn Garden City and the Hertford East/Stevenage routes.

I am fairly sure that both routes could handle eight tph, with the only proviso, that there is enough terminal capacity to turn the trains.

Looking at the layout of Welwyn Garden City station, I am certain that it could be modified to be able to handle eight tph.

I would hope that the new platform at Stevenage station, built to handle trains to and from Moorgate, can cater for four tph. As there are turnback platforms at Gordon Hill and Hertford North stations, I’m sure the other four tph could be handled.

The Piccadilly Line And The City of London

It has always been difficult to get between the Northern section of the Piccadilly Line and the City of London.

In the 1960s, I used to use my bicycle. By public transport, you generally had to use the bus or the 641 trolley bus to Moorgate.

With the improvement of the Northern City Line and Finsbury Park station, the fastest route to Moorgate is probably to change between the Piccadilly and Northern City Lines at Finsbury Park station.

Increasing the frequency of Northern City Line services between Finsbury Park and Moorgate would create a high-capacity route to the City for those commuting from the Northern section of the Piccadilly Line.

The Piccadilly Line And Crossrail

There is no connection between the Piccadilly Line and Crossrail.

A trip between Oakwood and Canary Wharf would be difficult.

As with getting to the City of London, the improvement of the Northern City Line and Finsbury Park station offers a route to Crossrail.

Oakwood and Canary Wharf would probably be done with changes at Finsbury Park and Moorgate.

The Victoria Line And The City of London

There is a cross-platform interchange at Highbury & Islington station between the Victoria and Northern City Lines.

With an increased frequency of Northern City Line services between Finsbury Park and Moorgate, I would expect that more people would use this route.

The Victoria Line And Crossrail

There is no connection between the Victoria Line and Crossrail.

The easiest route will be to take the route in the previous section and join Crossrail at Moorgate.


It does look that with the current routes sixteen tph to and from Moorgate could be a practical limit.

But that would still be a train every three minutes and forty-five seconds between Finsbury Park and Moorgate.

This increased frequency could be needed to create a high capacity link between the Northern sections of the Piccadilly and Victoria Lines and the City of London and Crossrail.


November 23, 2021 - Posted by | Transport/Travel | , , , , , , ,


  1. remains to be seen whether we will ever need these higher frequencies on any of these routes of course so digital signalling should only be installed when existing assets are life expired – which it is over the old Northern City Line

    Comment by Nicholas Lewis | November 23, 2021 | Reply

    • I understood that digital signalling is being installed on the Northern City Line, as its trains will use the East Coast Main Line which is being digitally signalled.

      As a Control Engineer, I suspect that digital signalling will open up some interesting ways to operate trains.

      Comment by AnonW | November 23, 2021 | Reply

      • Unless you have one type of stock it will never realise the benefits that the Victoria Line delivers. Im not even sure that ECML is going to no lineside signals so no wonder the costs of these schemes scales ever higher peaks with little if anything ever to show for the money.

        Comment by Nicholas Lewis | November 23, 2021

  2. In the early 1970s, I shared an office at ICI, with a team who were sequencing a complicated chemical plant. As a Control Engineer, I saw the benefits and the same techniques can be applied to railway signalling.

    I believe that the two bottlenecks on the East Coast Main Line at Digswell and Newark, can be sorted by the use of digital signalling.

    Comment by AnonW | November 24, 2021 | Reply

    • Indeed and its real travesty that the automatic route setting feature that was a key output from BRs move to IECC’s has lapsed considerably on newer schemes. These sections maybe controlled from fancy ROCs now but on the ground they are still 1970’s technology and would benefit from traffic management algorithms designed to optimise throughput especially under perturbation.

      Comment by Nicholas Lewis | November 24, 2021 | Reply

  3. Only one train per hour on to Stevenage. Is that currently a temporary measure?
    I can’t see anything on line regarding works on that section.
    Because a lot of money was spent providing a new bay platform there.

    Comment by Dave | November 24, 2021 | Reply

    • Its the service via Hertford North and the bay platform was to keep it separate from ECML traffic as its occupancy of the DS once an hour ate up capacity. I used it a couple of times when 313’s were still in traffic and it was deserted between Stevenage at Hertford Nth but guess it will be well used for around school/college hours and working hours

      Comment by Nicholas Lewis | November 24, 2021 | Reply

      • I do wonder if there could be a need for a South Stevenage station, which could be Parkway station to encourage people out of their cars.

        We also have the problem of the Digswell Viaduct and Welwyn North station. I wonder if it were ever to be rebuilt, which looks unlikely at present but a South Stevenage station might be rather useful to avoid too much disruption for passengers.

        A fully-digital signalled Hertford Loop may also have more capacity and perhaps could be used by some of the stopping services from the East Coast Main Line.

        If Network Rail could find an acceptable way to close Welwyn North station, this might ease the problems of Digswell, with the only trains going over the viaduct being expresses to and from Stevenage, Cambridge, King’s Lynn and the North

        Comment by AnonW | November 24, 2021

    • The new setup at Stevenage is probably designed for at least four trains per hour, as no-one can predict what will happen in the future, with new housing and other developments.

      Comment by AnonW | November 24, 2021 | Reply

  4. Re connection of Victoria line and Crossrail/ELizabeth line it will be possible via the Hanover Square exit to Bond Street station.This is at the east end of the station and very close to Oxford Circus station.

    Comment by Mr Hugh P Steavenson | November 24, 2021 | Reply

    • It may be possible for an agile seventy-four year old London Mongrel like me, but it is not a feasible route for someone in a wheelchair or with twins in a double-buggy, as Oxford Street is not a step-free station.

      Finsbury Park, Highbury & Islington and Moorgate will all be step-free interchanges when Crossrail opens.

      Comment by AnonW | November 24, 2021 | Reply

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