There has been lots of talk about turning the Abbey Line into a Guided Busway system. This would involve replacing the current railway line with a concrete guided busway. In this post we provide a review of the busway option, in future posts we review of the current railway and in the final post a comparison between the two.

To our knowledge this would be the first time that an active railway line would be taken up to install a guided busway. Normally a guided busway is installed because it is cheaper than building a full rail solution. In the past previously removed train lines (such as a result of the Beeching cuts) have had a guided busway installed but this was years after the removal of the train line.

To try to keep the explanations simple we have deferred the supporting math into the footnotes, so it is there if you want to understand our working but also not cluttering the text for those people who are happy to accept our numbers.

Without significant changes to the bridges along the Abbey Line it would only permit single story busses and not double deckers. As such, for the purposes of comparison we will use one four car train being of equal capacity of five busses. 1

Things which would not change by the Abbey Line being a Guided Busway System and continuing as a railway line.

  • Reliability
    • Since the concrete guided bus system is not a road it means that there is no, or limited, possibility for a bus to over take another.  As such if a bus breaks down it must first be towed out of the way. As such the guided bus way provides no advantages in such conditions.
  • Running costs
    • For the same capacity the running costs for a train are about the same as the running costs for five busses. 2

Advantages of the Guided Bus system

  • Control
    • Whereas bus services are in the control of the County Council the rail network is controlled by the Department for Transport (DfT).  Since this is at a national level there are higher priorities for the DfT, Hertfordshire County Council can not tell the DfT what to do but can only champion changes which they believe will provide benefits.
  • Expansion
    • The Abbey Line is seen as a small and loss making part of a rail franchise, as such there is no incentive for franchise holders to invest a lot of effort into it.  With the launch of community rail partnerships this has improved but there is still a way to go. One challenge is for the expansion and the number of challenging hurdles for this to be completed, as shown with the Met line extension.

Disadvantage of the Guided Bus system

  • Reliability
    • Not just any bus can use the guided busway, they need to be fitted with guide wheels which effectively steer the bus.
  • Cost
    • The conversion would cost a minimum of £90m.  The Luton busway was expected to cost £51m but resulted in a cost of £91m.  Similarly the concrete busway such as the Cambridge to St Ives railway was estimated to cost £64m and ended up costing £181m.  As such it is likely £90m on the conversion of the Abbey Line is going to be an underestimate.
    • Generally a guided busway is cheaper than rail to construct, however since the railway line is already present this cost advantage is zero and instead there would be an increased cost in removing the track and preparing platforms suitable for the busses.
    • The Abbey Line was never designed to take a busway so at some places additional land might be needed for either the busway or for additional sound barriers.
  • Safety
    • There have been a couple of incidents on the Luton busway.  One was of a bus “jumping” out of the guided channels.  Secondly of a moving bus crashed with a stationary bus.
  • Capacity
    • To maintain the current level of capacity there would need to be a bus in both directions every 8 minutes.  Currently at peak times the Abbey Line is very busy so this could cause problems at such times.
  • Customer experience
    • Guided busways tend to experience lateral motion/wobble, which can make the journey unpleasant.
  • Lack of continuity of service during conversion
    • The conversion from rail to bus system will likely take 3-4 years (based on similar projects).  During this time there would be no service by train or bus along the Abbey Line.
  • Increased congestion at crosses (Bushey Mill Lane etc)
    • With a bus every 8 minutes this would mean that there would be an increased number of times where the Busway crosses the existing roads and paths which would increase congestion at these points.

This series continues with a look at the Railway solution.

1 This is based on the capacity of a standard four car train, such as the one used on the Abbey Line, which has 277 seats and space for 117 standing, so a total capacity for 394 people. In comparison a bus has 49 seats and space for 27 standing, giving space for 76 passengers. So for each train there would need to be 5 busses for the same amount of capacity (based on total travellers 394/76 = 5.2 or 277/49 = 5.7 for just seated passengers).
2 2016-17 = £3.03b for 2016-17 = 1.24b miles which is the equivalent of about £2.44 per mile. The length of the Abbey line is 6.5 miles so the total cost per bus per journey is £15.88.  There are 42 runs of the train each day 15.88*42 = £667 per bus per day for 5 busses = £3,335 per day.  The cost of running the train = £3,287 per day.