Cost of service and utility diversion do not rule out trams, Edinburgh notwithstanding


Response to Peter Fox, Letter to the Bath Chronicle of 3 May 2018

Mr Fox, in his letter to the Chronicle of 3 May, is quite correct in drawing attention to the cost of diverting utilities’ apparatus as a heavy burden on tramway proposals. But this is not necessarily the sole reason why proposals to build tramways fail.

There have been two modern attempts to build a tramway serving Bristol. I was invited by the promoter of the first scheme, the Advanced Transport for Avon which obtained statutory powers in an Act of 1989, to use my experience in managing diversions, shortly before the scheme was abandoned. As a result I can be fairly sure that the cost of diversions was not the main factor in the decision to drop it, as it was unknown at that stage. It seems that the later proposal for the Bristol Supertram was abandoned in 2004 so that the money set aside for its development could be used to cover a projected council tax increase, which again implies that the cost of diversions was not a major factor.

In any project funded publicly, at least in part, the essential requirement is that the benefit deriving from it exceeds the cost of providing it by an acceptable margin. This means assigning a cost to all elements of the project, of which diversion of apparatus is only one. If the benefit to cost ratio can be demonstrated to be satisfactory, the individual cost of the various elements is of no real concern.

The Edinburgh Tramway is the subject of a Public Inquiry, which is now coming to an end. It is important to wait for the final report to be released, rather than simply assuming the cost and duration of the diversionary works could not have been reduced by better management.

What happens to apparatus below or close to a tramway is determined by the New Roads and Street Works Act 1991. The Act merely requires the tramway promoter and the owner of apparatus to “identify any measures needing to be taken” to allow the tramway construction to be undertaken. There is no obligation on the utility company to move the apparatus, nor will they necessarily do so. As an example, sewers are normally located well below the level at which they could be affected by the tramway operations. If the sewer is in a satisfactory condition and can be accessed via a conveniently placed manhole, it is normal to leave it beneath the tracks. Similarly much of BT’s network is several meters deep and under favourable circumstances will not be diverted.

Having managed or advised on diversion of apparatus for several UK tramways, including Manchester Metrolink, Midland Metro, Strathclyde, Leeds Supertram, Sheffield Supertram extensions and Nottingham Express, I have great confidence in the possibility of keeping diversion costs at a manageable level. Over the last 30 years of tramway development, many cost saving measures have been agreed between promoters and utility companies. But this requires close co-operation between both parties from a very early stage in the development of the tramway, and failure to ensure this happens is the most likely way to end up in the situation met by Edinburgh and some of the other tramways.

David Rumney


( David Rumney is a chartered engineer, and a (retired) member of the Institution of Civil Engineers, the Institution of Highways and Transportation and the Institute of Arbitrators. Involved in the planning of many UK successful tram systems such as the  Manchester Metro-link, Birmingham, ( but  not Edinburgh) and varying levels of involvement in Croydon, Liverpool and Nottingham, Leeds Supertram ( not built  – Alistair Darling cancelled the scheme along with that of Liverpool.) . Expert in the issue of underground utilities diversions ( full expertise listed below in Advisory Group))



Dear all,

                My expertise in this is that as part of the design and costing work for the proposed Greenwich Waterfront Transit (GWT)project (tram technology option) I did a desk top cost evaluation of the costs of utilities relocations in Woolwich. It was agreed that for that project utilities costs would be significant and that was a reason why the alternative option of an electronically guided busway was eventually preferred; but subsequently also abandoned for different reasons. There are some important facts about utilities costs which are not mentioned in David Rumney’s letter which are :-

  1. There are about 20 different types of “utilities”; some types are very costly to relocate and some have virtually no cost to relocate.
  2. Not every type of utility is found in every street. We do not know yet what we have in Bath.
  3. In virtually all new highways constructed since about 1960 no utilities are located under the carriageway at shallow depth; and therefore no relocations are necessary or required.
  4. Therefore because of 1-3 above the % of a tram project’s cost which goes to utilities relocations is very variable on a range from 0% to more than 25%
  5. Therefore in a city such as Milton Keynes which is entirely built since 1960 a tram system would have no utilities relocation costs at all.
  6. Therefore in a city such as Edinburgh, which has an abundance of every type of ancient and dilapidated utilities it is inevitable that utilities reconstruction costs will be not just above average but exceptionally high.
  7. Therefore the part of the proposed GWT tram route in old Woolwich had exceptionally high utilities relocation cost estimates and the part in newer Thamesmead had almost zero relocation costs.
  8. Legislation pursuant to the New Roads and Street works Act defines how the costs of any agreed, or not agreed, utilities relocation costs will be negotiated and “shared” between the tram promoter and the highway owners. Parliament can and has in the past, changed the rules of engagement. This applies whether public money is involved or not.
  9. Obviously Edinburgh could have negotiated poorly, underestimated the risks and signed up to a very poor deal. Some commentators say that they did just that, and set a new UK and world record for incompetence and high utilities relocation costs.
  10. MOST IMPORTANT; technology improves all the time and allows tram projects all over the world to do everything better and at lower cost. Tram track technology is no exception. All the above historic costs are now irrelevant because in future about 90% of what used to be “necessary” relocations are no longer “necessary” if LR55 track is used; and it can be used almost everywhere, including in Bath.
  11. Unfortunately even as the Preston Tram line 1 is being built with LR55 track for ULR tramcars, to eliminate all utilities relocation costs from that tram system, the WS Atkins report to Bath Council has assumed that Bath will only have old style slab track with costs similar to Edinburgh. That assumption is not inevitable and is therefore wrong and unhelpful.

Bob Chard,  Member of the ULR Group of UK Tram



Such utility works have to be done in reasonable co-operation with other
utilities, including tramways. The HMRI has provided a “possession
arrangement” for utility works under active tram tracks. This includes
diverting road traffic away.

Obviously for catastrophic utility failures, eg. gas main/water main
bursting, trams would have to stop, for about a week. Such failures are
however 1 in 40 year events. A economic exercise was undertaken for a
proposed tramway to Liverpool Airport. This showed that if the cost of
utility diversion was more than £160k per km, then it is better to leave
plant in place and lose a week’s tram revenue every 40 years.

Trampower includes a conservative figure of 9% of track costs for utility
accommodation works, with LR55 tracks, since as Bob Chard has pointed out,
there are no utilities in the top 300mm of a road, except for magnetic loop
detectors for traffic signals, which are being phased out in favour of radar
detection. And from many discussions with Utility Companies, not having to
move plant is their dream, provided access is available between rails. LR55
rails self support over 1m wide trenches.
Lewis Lesley

Prof. Lewis Lesley BSc, AKC, PhD, CEng, MICE, FRSA, FCIT, MTPS