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Article date 14 January 2015
Revised 25 March 2015

Improving the service between Watford Junction and St Albans Abbey

Currently the service between Watford Junction and St Albans Abbey is provided by a single train running from Watford Junction to St Albans Abbey, then returning to Watford Junction. From one Watford departure to the next is a time interval of no less than 45 minutes. Many users would prefer a more frequent service. This article discusses options for achieving this.

The existing line from Watford Junction to St Albans Abbey station, known as the Abbey line, is currently single track i.e. permitting only a train in the direction Watford Junction to St Albans Abbey or in the direction St Albans Abbey to Watford Junction, but not two trains in opposite directions at the same time. The single track line thus limits the frequency of services, currently provided by a single train running from Watford Junction to St Albans Abbey, then returning to Watford Junction. From one Watford departure to the next is a time interval of no less than 45 minutes.

Stations on the Abbey line are : Watford Junction, Watford North, Garston, Bricket Wood, How Wood, Park Street, St Albans Abbey. Currently all trains (i.e. the one and only train) call at all stations.

There has been a debate for some (in fact, many) years concerning the future of the service on the Abbey line. There has been a lengthy, sustained campaign for the re-introduction of a signalled connection onto the West Coast Main Line (WCML) at Watford Junction to enable services on the Abbey line to be extended to London. An argument against this has been the cost of such a signalled connection, as also the cost of signalling required to permit a more frequent service on the Abbey line.

The Abbey line closed from 29 November to 29 December 2014. The junction with the WCML changed from manual to mechanised operation as part of a Network Rail project to replace track, signalling equipment and overhead power lines in the area. In other words, a signalled connection has been provided.

Currently pasengers arriving at Watford Junction wishing to continue their rail journey e.g. to London Euston have to change trains there. The provision of a signalled connection from the Abbey line onto the WCML offers the prospect of through services, that is, services extended on to the WCML e.g. direct to London Euston. Passengers using any such service to their required destination would no longer need to change trains at Watford Junction.

The High Speed 2 rail project will result in a rework of the services offered to London via the WCML. It has been stated that this will result in an increase in frequency of some existing services to London Euston as also the opportunity for new services direct to London Euston.

The Crossrail project will, it is anticipated, result in some Crossrail services running on to the WCML i.e. via Watford Junction.

This, then, is a key moment in the life of the Abbey line.

This article discusses improving the service between Watford Junction and St Albans Abbey, both by increase in frequency of service and by the introduction of a through service. A through service might be a service direct from London Euston onto the Abbey line to St Albans Abbey, or a Crossrail service onto the Abbey line to St Albans Abbey. We will discuss potentially appropriate railway infrastructure for increased service frequency of the local all-stations-stop service between Watford Junction and St Albans Abbey as also for a through service.

Obvious choices for a through service would be a service from and to London Euston or a Crossrail service. The choice of either of these, or of any other suitable through service, is not discussed in this article, that is, we will discuss the capability of the line so as to permit a through service but not which specific through service might be selected.

This article references animations. These are available here (opens in new tab or window) : List of Abbey line animations

The existing service

The existing railway line between Watford Junction and St Albans Abbey, known as the Abbey line, is illustrated below. At Watford Junction, only those railway tracks relevant to our discussions are shown.

It should be borne in mind that no scale has been applied, this being in order to be able to illustrate railway infrastructure.

The Abbey line, the existing railway line between Watford Junction and St Albans Abbey

Our first animation illustrates the existing service on the Abbey line. Trains are shown as making steady progress along the line. No time is allocated for specifically calling at stations. Trains progress at reasonable speed between stations, slow down on approach, call at a station then accelerate on departure. Instead, we have illustrated an average speed.

The timetable for our first animation follows. Times are in minutes and seconds in the format MM:SS from the start of the animation.

Watford Junction dep  Watford North  Garston   Bricket Wood  How Wood  Park Street   St Albans Abbey arr
03:00  05:30  07:30   11:00  13:30  15:00   19:00


St Albans Abbey dep  Park Street  How Wood   Bricket Wood  Garston  Watford North   Watford Junction arr
24:00  28:00  29:30   32:00  35:30  37:30   40:00

Our second animation also illustrates the existing service on the Abbey line. Here, we have allocated time for trains to call at intermediate stations i.e. dwell time. The time allocated is 30 seconds. As a result of our re-calculations, the journey time between Watford Junction and St Albans Abbey has reduced from 16 minutes to 15 minutes 30 seconds. This is regarded as simply a rounding error. When calculating the time available between a service arriving at Watford Junction or St Albans Abbey and commencing service in the opposite direction, referred to in this article as the turnround time, we will not include the 30 seconds as part of the calculation.

The timetable for our second animation follows. Again, times are in minutes and seconds in the format MM:SS from the start of the animation.

Watford Junction dep   Watford North arr  Watford North dep   Garston arr  Garston dep   Bricket Wood arr  Bricket Wood dep   How Wood arr  How Wood dep   Park Street arr  Park Street dep   St Albans Abbey arr
03:00   05:00  05:30   07:00  07:30   10:30  11:00   13:00  13:30   14:30  15:00   18:30


St Albans Abbey dep   Park Street arr  Park Street dep   How Wood arr  How Wood dep   Bricket Wood arr  Bricket Wood dep   Garston arr  Garston dep   Watford North arr  Watford North dep   Watford Junction arr
24:00   27:30  28:00   29:00  29:30   31:30  32:00   35:00  35:30   37:00  37:30   39:30

A more frequent service

There has been much pressure to accept conversion of the Abbey line to offer a light rail (tram) service. The facts have changed since that was proposed, particularly given resignalling at Watford. It makes sense for the Abbey line to offer a more frequent (conventional) rail service and with through services on to the WCML. Trams terminating at Watford are a poor show in comparison with that. We think it would be appropriate for the tram proposal to be quietly and definitively dropped.

A more frequent service cannot be provided by a single train. Here we will consider what could be achieved with two trains. If two trains on the line travelling in opposite directions were to pass at the mid point, which is Bricket Wood, a more frequent service becomes possible. The infrastructure is illustrated below.

The Abbey line with the addition of a passing loop at Bricket Wood

The infrastructure at Bricket Wood that permits two trains to pass is known as a passing loop. Trains in opposite directions pass using the passing loop. There are two platforms at Bricket Wood station, one for each direction of travel. The first-arriving train has to wait for the second-arriving train before being able to continue beyond Bricket Wood. Although the trains would be timed to arrive at Bricket Wood at the same time, each calling at the appropriate platform for the direction of travel, there is a possibility of late running. To reduce the potential impact of late running, we add a minute of waiting time to the timetable in each direction at Bricket Wood.

We have included two platforms at Watford Junction. The bay platform, i.e. not a through platform, considered as platform 11, would be used by the trains providing the local service between Watford Junction and St Albans Abbey. The other platform, considered as platform 12, is a through platform and therefore connected to the West Coast Main Line, useful for a through service e.g. from London Euston or for a Crossrail service and which would run direct to St Albans Abbey.

The journey time between Watford Junction and St Albans Abbey is 16 minutes. If two trains on the line travelling in opposite directions are to pass using a passing loop we add a minute to the end-to-end journey time to cater for either service running late. With a turnround time of 13 minutes, this would enable a service every 30 minutes in each direction, i.e. 17 plus 13 equals 30. This would be an improvement on the current service. A turnround time of 13 minutes is lengthy. With a turnround time of 8 minutes, this would enable a service every 25 minutes in each direction. It might be considered that a service every 30 minutes provides an easier-to-remember timetable than a service every 25 minutes. On the other hand, a service every 25 minutes is more frequent. For the purpose of this article, we have opted to illustrate a service every 25 minutes. This forms the basis for our third animation.

The timetable for our third animation follows. Again, times are in minutes and seconds in the format MM:SS from the start of the animation. Again we have included a 30 second dwell time at intermediate stations. This time we have added an additional 30 seconds to the final stage prior to arrival at each terminus station, so that the journey time is 17 minutes in each direction. The reason is that there are two platforms at Watford Junction and so it is helpful to add an extra 30 seconds to arrive at the bay platform. For this reason, we have added 30 seconds also for the arrival at St Albans Abbey station.

Watford Junction dep   Watford North arr  Watford North dep   Garston arr  Garston dep   Bricket Wood arr  Bricket Wood dep   How Wood arr  How Wood dep   Park Street arr  Park Street dep   St Albans Abbey arr
03:00   05:00  05:30   07:00  07:30   10:30  12:00   14:00  14:30   15:30  16:00   20:00


St Albans Abbey dep   Park Street arr  Park Street dep   How Wood arr  How Wood dep   Bricket Wood arr  Bricket Wood dep   Garston arr  Garston dep   Watford North arr  Watford North dep   Watford Junction arr
03:00   06:30  07:00   08:00  08:30   10:30  12:00   15:00  15:30   17:00  17:30   20:00

Adding a through service

In our third animation, there was no through service from the West Coast Main Line and which would make use of platform 12. A through service might be from London Euston, or a Crossrail service, and would run direct to St Albans Abbey. In our fourth animation, we include a through service, coloured in red. The local service between Watford Junction and St Albans Abbey is coloured green, as previously. We have maintained the 25-minute pattern for services. During the time that the through service is operating on the Abbey line, a train that would have been providing the local service remains out of service at platform 11.

The animation divides into three phases. In the first phase, the local service operates as two trains, one from Watford Junction to St Albans Abbey, the other in the other direction. This is as for our previous animation. In the second phase, a through service (coloured in red) operates from Watford Junction to St Albans Abbey, whilst a train (coloured in green) provides the local service in the opposite direction. In the third phase, the through service returns from St Albans Abbey to Watford Junction, whilst a train provides the local service in the opposite direction. The times shown in this, our fourth, animation are from the start of each of the three phases.

The timetable for this animation is as for the third animation on a 25-minute cycle. The through service is assumed to provide the all-stations-stop service that would have been provided by a locally-operating train. This service is allocated three minutes waiting time at Watford Junction on arrival from the WCML prior to continuing towards St Albans Abbey, as also three minutes on arrival at Watford Junction from St Albans Abbey prior to continuing on to the WCML.

Making better use of the trains

The previous animation illustrates that a train remains out of service at Watford Junction throughout the time that a through service is operating on the Abbey line. The through service is assumed to provide the all-stations-stop service that would have been provided by a locally-operating train. The through service might be, for example, a Crossrail service or an 8-coach train from London Euston. Intermediate stations could therefore be subject to platform lengthening simply to accommodate longer trains than currently operate on the line. Alternatively, selective door opening would be necessary.

If the through service were to be a limited stop service, that is, not calling at all intermediate stations, the service provided at such intermediate stations would reduce from a service every 25 minutes to be less frequent as a result of the through service operating on the line.

Although we have three trains available, we have continued to provide a train in each direction only every 25 minutes, even though a higher-frequency service would seem to be potentially available, that is, by making better use of the trains available. How then could we make better use of the available trains?

Ideally there would be three trains per hour in each direction as long as three trains are available to provide this, that is, for the duration of the time that a train providing a through service from the WCML is operating on the line. Prior to such a through service entering the line at Watford Junction, we might assume a service every 25 minutes. After such a service leaves the line at Watford Junction, we might reasonably assume resumption of a service every 25 minutes. The train providing the through service in conjuction with the trains providing the regular Abbey line local service would provide a service approximately every 20 minutes.

The terrain from Watford Junction to How Wood station is reasonably flat. Upgrading much of the line from the current single track (i.e. permitting only a train in the direction Watford to St Albans Abbey or in the direction St Albans Abbey to Watford, but not two trains in opposite directions at the same time) to dual track (i.e. permitting trains in each direction at the same time) would seem to be feasible. In contrast, from the St Albans side of How Wood station until the approach to St Albans Abbey station the terrain is far from flat : the line is on an embankment, then in cutting (in the vicinity of Abbots Avenue, St Albans) prior to returning to flat terrain for the approach to St Albans Abbey. To limit costs, it is perhaps better to assume that no upgrade to dual track would occur from the St Albans side of How Wood station until the approach to St Albans Abbey station. This has the effect of constraining how we might envisage an enhanced railway infrastructure.

Taking further the idea of two platforms at Bricket Wood station, with two platforms at How Wood station and with dual track between these two stations, we seem to have the basis for a service approximately every 20 minutes. As a corollary of this, we also need dual track from Watford Junction until the approach to Watford North station. The line crosses Balmoral Road between Watford Junction and Watford North and we hope the bridge is of sufficient width to permit dual track. The infrastructure is illustrated below.

The Abbey line with two platforms at Bricket Wood and two platforms at How Wood

We now present a possible timetable for services using this infrastructure. Again, times are in minutes and seconds in the format MM:SS. Again we have included a 30 second dwell time at intermediate stations. In this and subsequent timetables only stations immediately relevant to our discussions are included. Trains are however timed to call at all stations. Times at stations not shown may be deduced.

Service  Watford Junction dep   Watford North arr  Watford North dep   Bricket Wood arr  Bricket Wood dep   How Wood arr  How Wood dep   St Albans Abbey arr
Local (green)  00:00   02:00  02:30   07:30  08:00   10:00  10:30   16:00
Through (red)  20:00   22:00  22:30   27:30  28:00   30:00  30:30   36:00
Local (green)  37:30   39:30  40:00   45:00  45:30   47:30  48:00   53:30


Service  St Albans Abbey dep   How Wood arr  How Wood dep   Bricket Wood arr  Bricket Wood dep   Watford North arr  Watford North dep   Watford Junction arr
Local (green)  02:30   07:30  08:00   10:00  10:30   15:30  16:00   18:30
Local (green)  24:00   29:00  29:30   31:30  32:00   37:00  37:30   40:00
Through (red)  41:30   46:30  47:00   49:00  49:30   54:30  55:00   57:30

Local services in the above timetable pass at the mid-point between Bricket Wood and How Wood or at the mid-point between Watford Junction and Watford North (as illustrated by our fifth animation, described below). The through service passes a local service in the vicinity of How Wood. In deriving this timetable, we planned for a train from St Albans to arrive at How Wood a minute prior to a train arriving at How Wood from Watford i.e. a local service passing the through service. We did this so as to reduce the likelihood of late running of a service from St Albans having an impact on a service to St Albans (in contrast to the case of a passing loop at Bricket Wood, earlier, where late running in either direction would have an impact on the service in the opposite direction). Therefore the journey time is estimated as 16 minutes, without the need to add an additional minute.

The above timetable results in a turnround time of 5.5 minutes for the through service at St Albans Abbey (36:00 to 41:30). This is considered to be somewhat tight, given that the driver has to walk to the other end of the train and that the train may be longer than otherwise operates on the line, being a through service. In the alternative timetable that follows, we have tightened up the operation so that the through service and a local service in each direction arrive at How Wood at the same time. This results in a turnround time for the through service at St Albans of 7.5 minutes (35:00 to 42:30), which is more satisfactory. In both timetables, the turnround time for the locally-operating service is 8 minutes (16:00 to 24:00) or 9 minutes (53:30 to 02:30).

The only difference between the alternative timetable that follows and the previous timetable is that the through service has been retimed to run one minute earlier from Watford Junction and one minute later from St Albans.

Service  Watford Junction dep   Watford North arr  Watford North dep   Bricket Wood arr  Bricket Wood dep   How Wood arr  How Wood dep   St Albans Abbey arr
Local (green)  00:00   02:00  02:30   07:30  08:00   10:00  10:30   16:00
Through (red)  19:00   21:00  21:30   26:30  27:00   29:00  29:30   35:00
Local (green)  37:30   39:30  40:00   45:00  45:30   47:30  48:00   53:30


Service  St Albans Abbey dep   How Wood arr  How Wood dep   Bricket Wood arr  Bricket Wood dep   Watford North arr  Watford North dep   Watford Junction arr
Local (green)  02:30   07:30  08:00   10:00  10:30   15:30  16:00   18:30
Local (green)  24:00   29:00  29:30   31:30  32:00   37:00  37:30   40:00
Through (red)  42:30   47:30  48:00   50:00  50:30   55:30  56:00   58:30

This paragraph aims to demonstrate that the alternative timetable is workable. To reduce the likelihood of late running of the local service from St Albans holding up the through service to St Albans, the departure at 24:00 of the local service from St Albans might if necessary be moved forward by a minute to 23:00. This service would then be scheduled to arrive at How Wood one minute prior to the arrival of the through service to St Albans (i.e. as in the previous timetable). This local service might then be delayed by a minute to arrive at Watford at the same time i.e. 40:00 since it has to pass a local service in the opposite direction between Watford Junction and Watford North. In the opposite direction, any late running of the through service departing St Albans at 42:30 would cause delay at How Wood to the local service to St Albans, however, this service has a turnround time of 9 minutes at St Albans, therefore with the prospect that a minor incidence of late runnning can be recovered to re-establish on-time runnning by a slightly reduced turnround time at St Albans.

The result seems to be that the alternative timetable is workable and this, therefore, provides the basis for our fifth animation. This animation differs from previous animations in that this is a 60-minute cycle, (thereby also implying that the through service might run as often as hourly). Times may therefore be regarded as minutes and seconds past the hour and not solely as minutes and seconds from the start of the animation.

In this animation, the through service from the West Coast Main Line is coloured red, the local services coloured green. The animation commences with a through service leaving the Abbey line.

If the through service were to be a limited stop service, it would be scheduled to enter the line at Watford Junction a few minutes later and leave the line at Watford Junction a few minutes earlier, still timed to pass a local service at How Wood. If the through service did not call at Park Street in either direction, the turnround time available at St Albans Abbey would increase by approximately two minutes. Intermediate stations on the line at which the through service did not call would still benefit from two services an hour in each direction, provided by the locally-operating trains.

Passing at the mid-point between Bricket Wood and How Wood

In the previous scenario, the through service passed a local service at, or in the vicinity of, How Wood. We will now discuss an adjustment to the previous scenario. The adjustment is that the through service would pass a local service at the mid-point between Bricket Wood and How Wood. A timetable for this follows. Trains do not pass between Watford Junction and Watford North, therefore times at Watford North are not included.

Service  Watford Junction dep   Bricket Wood arr  Bricket Wood dep   How Wood arr  How Wood dep   St Albans Abbey arr
Local (green)  00:00   07:30  08:00   10:00  10:30   16:00
Through (red)  20:00   27:30  28:00   30:00  30:30   36:00
Local (green)  40:00   47:30  48:00   50:00  50:30   56:00


Service  St Albans Abbey dep   How Wood arr  How Wood dep   Bricket Wood arr  Bricket Wood dep   Watford Junction arr
Local (green)  02:30   07:30  08:00   10:00  10:30   18:30
Local (green)  22:30   27:30  28:00   30:00  30:30   38:30
Through (red)  42:30   47:30  48:00   50:00  50:30   58:30

It is an open question as to whether there would be two platforms at How Wood in order to implement such a timetable. If not, we might envisage an infrastructure as follows. Below, we have included a red-coloured through service and a green-coloured local service passing at the mid-point between Bricket Wood and How Wood for illustrative purposes, since we have not provided an animation for this scenario.

The Abbey line with trains passing at the mid-point between Bricket Wood and How Wood

To visualise how this timetable would operate, consider the previous (fifth) animation with the point at which the through service and a local service pass relocated leftwards to the mid-point between Bricket Wood and How Wood. From this, it can be deduced that the local services passing at the mid-point between Watford Junction and Watford North would no longer pass at this point. Instead, a local service from St Albans arrives at Watford Junction at 38:30 shortly prior to the departure of the other local service from Watford at 40:00.

It is noteworthy that we have a service exactly every 20 minutes, which might be regarded as tidier than the earlier timetables for three trains an hour. The turnround time at St Albans Abbey is 6.5 minutes for each service.

However, this scenario presents us with an issue, concerning platforms at Watford Junction. A local service departs Watford Junction platform 11 at 00:00. A local service arrives at platform 11 at 18:30, platform 12 being occupied by the impending through service departure at 20:00. The local service at platform 11 will form the 40:00 departure. The local service arriving at 38:30 is therefore platformed at the only available platform, being platform 12. This service will form the next 00:00 departure, this time from platform 12. When the through service returning from St Albans arrives at 58:30, the only available platform is platform 11, which is a bay platform, not a through platform. It needs to arrive at platform 12.

To resolve this issue, the infrastructure illustrated includes red-dotted tracks to the left of Watford Junction, designed to illustrate the possibility of both platforms 11 and 12 being connected to the WCML. Otherwise, a solution to this issue is for the local service arriving at platform 11 at 18:30, after passengers have alighted, to transfer to platform 12 prior to passengers boarding for the 40:00 departure. The driver walks to the other end of the train and takes the train back down the line a short distance. The driver then walks to the other end of the train and makes use of a local track traversal to bring the train into platform 12, then walks - a third time - to the other end of the train in order to prepare for the 40:00 departure from platform 12. Hopefully the train is not lengthy. Good exercise, in any case. The local service arriving at 38:30 is platformed at platform 11. Now when the through service returning from St Albans arrives at 58:30, it can be platformed at platform 12, as required.

Two passing loops, one at Bricket Wood and one at How Wood

The Abbey line passes beneath Station Road north of Bricket Wood station and then crosses the M25 motorway between Bricket Wood and How Wood on a bridge currently only suitable for single track. If dual track is not feasible at both of these points - in particular, requiring replacement of the current bridge over the M25 or a second bridge alongside the existing one - an alternative option to those above might be two passing loops, one at Bricket Wood and one at How Wood. The infrastructure is illustrated below.

The Abbey line with passing loops at Bricket Wood and How Wood

We now present a possible timetable for services using this infrastructure. Again, times are in minutes and seconds in the format MM:SS. Again we have included a 30 second dwell time at intermediate stations. Again only stations immediately relevant to our discussions are included. Trains are however timed to call at all stations. Times at stations not shown may be deduced.

Service  Watford Junction dep   Watford North arr  Watford North dep   Bricket Wood arr  Bricket Wood dep   How Wood arr  How Wood dep   St Albans Abbey arr
Local (green)  00:00   02:00  02:30   07:30  09:00   11:00  11:30   17:00
Through (red)  18:00   20:00  20:30   25:30  26:00   28:00  29:30   35:00
Local (green)  37:30   39:30  40:00   45:00  45:30   47:30  49:00   54:30


Service  St Albans Abbey dep   How Wood arr  How Wood dep   Bricket Wood arr  Bricket Wood dep   Watford North arr  Watford North dep   Watford Junction arr
Local (green)  00:00   05:00  05:30   07:30  09:00   14:00  14:30   17:00
Local (green)  23:00   28:00  29:30   31:30  32:00   37:00  37:30   40:00
Through (red)  42:30   47:30  49:00   51:00  51:30   56:30  57:00   59:30

Local services in the above timetable pass at Bricket Wood or at the mid-point between Watford Junction and Watford North. The journey time for all services is estimated as 17 minutes, with an additional minute due to trains passing in one of the passing loops. The turnround time for the through service at St Albans Abbey is 7.5 minutes (35:00 to 42:30) and for the local services is 6 minutes (17:00 to 23:00) or 5.5 minutes (54:30 to 00:00).

Our sixth animation illustrates the above timetable. It is similar to our fifth animation. Again this is a 60-minute cycle, (thereby also implying that the through service might run as often as hourly). Times may therefore be regarded as minutes and seconds past the hour and not solely as minutes and seconds from the start of the animation.

Outline conclusions

We have outlined a number of options for enhanced railway infrastructure that would permit both a more frequent local service on the Abbey line, as also a through service between the WCML and the Abbey line.

A passing loop at Bricket Wood with two platforms at Bricket Wood would permit a more frequent local service, e.g. every 30 minutes or every 25 minutes in each direction, the service being provided by two trains.

For the duration of time that a through service is operating on the line, we have three trains available : the train providing the through service together with the two trains providing the local service. The continuation of the service provided every 30 minutes or every 25 minutes would be possible by taking a locally-operating train out of service at Watford Junction. However, this would rely on the through service being an all-stations-stop service in order to maintain service frequency at intermediate stations along the line.

There are likely to be advantages in not constraining a through service to be an all-stations-stop service, for example if the through service were to be provided by a train of greater length than is otherwise utilised on the line. Therefore, to maintain something approximating to the frequency of the local service whilst a through service is operating on the line, there are advantages in enabling utilisation of all three available trains. Three services an hour on the line during the time that a through service is operating on the line would seem to be the means to achieve this. Any intermediate stations on the line at which the through service did not call would then still benefit from two services an hour in each direction, provided by the locally-operating trains.

Comments are welcome.



End of article.


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