The debate behind the HST cascade
With the cascade of HSTs for ScotRail services beginning this year, DAVID CLOUGH looks back at the debate within BR about HST redeployment following East Coast electrification 30 years ago
As part of East Coast Main Line electrification authorisation in the 1980s, provision was made for redeployment of the High Speed Train sets (HSTs) that would no longer be required once electrically hauled services began.
Within the scheme’s appraisal the sets were ascribed a high residual value, but poor utilisation was associated with their subsequent deployment.
An overall net present value of £ 38 million for electrification included £ 20m for the HSTs, of which £ 7.9m was ascribed to the InterCity Sector and £12.1m to the Provincial Services (later Regional Railways) Sector. These values for the HSTs were obtained against the single alternative of deferring the renewal of Class 47s and Mk 1 and Mk 2 rolling stock on the services concerned.
After the scheme was sanctioned in 1984, detailed planning began for the cascade. Dependant on what new work would be assigned, there could be a need to reallocate sets to different depots and therefore resource accordingly.
BR’s electrification project manager Don Heath, who was also project manager for (among others) the Advanced Passenger Train, kick-started the discussion in August 1984. when there was optimism that electrification could be completed ahead of schedule. Heath proposed a two-year timescale for putting a cascade plan into place.
Some guidance was given to the Provincial Director, who had opened a bilateral dialogue with the InterCity Director. This was that Provincial should determine how many HST sets the sector could use profitably, so that the total surplus over the next best alternative could be clearly identified.
A reappraisal of the electrification project in spring 1983 had identified 36 2+8 sets becoming surplus. Heath envisaged InterCity and London & South East (later Network Southeast, LSE) also carrying out studies, and taken together with those he requested be done by Provincial, the 36 most profitable workings could be identified. Alternatively, the results would reveal how many of the 36 could be used profitably.
For planning purposes, 11 sets were programmed to be released in October 1989, when electrification to Leeds was due for completion, with the remainder by May 1991. Four sets were to be retained for services that would extend beyond Edinburgh.
A scoping exercise had also been carried out in 1983, to assess what locomotive-hauled services might be turned over to HSTs.
HST availability was put at 82%, compared with 68% for locomotives (the quantities reflected totals, not just the number of diagrams). Included in the quantity of locomotives displaced were those required at locations such as Birmingham (where there was a change in direction), and terminal stations such as Liverpool Lime Street.
Detailed discussions began in January 1985, with Provincial flagging up that even a 1+4 HST formation would worsen the financial position of many of its services.
The Provincial Sector was concerned about the standard of the Edinburgh to Aberdeen services, where these were not formed by HSTs. Further, it was pointed out that the ECML Control Group had agreed that Class 47/7s, possibly in pairs, would be used to haul all through services north of Edinburgh.
InterCity had already identified a number of trains that could be taken over by HSTs. On the North East/South West axis, it included those to Poole, Cardiff and Penzance, those that crossed London, the European (Harwich to Glasgow), and some Western Region ( WR) internal diagrams. The Sector also wanted to strengthen the WR’s sets by the addition of an extra Standard Class vehicle.
LSE had done no detailed work, but felt that HSTs with a single power car would be worth considering for the Waterloo to Exeter line, and for Paddington to Oxford and then on to Birmingham. For the first group of these, six passenger-carrying coaches would be needed,
although the Sector recognised that there would be a shortfall of 50 seats during the peak, which (remarkably) it would be content to accept.
In addition, Provincial proposed reviewing all operations between Edinburgh and Aberdeen, as well as those from Glasgow and Edinburgh to Inverness.
One issue flagged up was that some HSTs were barred from Southern Region’s Central and South East Divisions’ electrified routes, due to bogie clearance concerns. If this remained an issue, the InterCity’s crossLondon trains would not be turned over.
Time moved on, and sensible planning seemed to get lost. Something of a spat between departments broke out, whereby the Provincial Director made it clear that his staff would not be conducting any further analysis beyond that already done.
Subject to haulage and adhesion parameters for 1+ 5 formations being clarified, his Sector would require a maximum of 29 power cars and a corresponding number of trailers. He was, however, examining the potential for acquiring Class 210 diesel multiple units (DMUs) as an alternative, because this could pre-date the 1991 HST cascade.
The InterCity Engineer responded that there was no adhesion issue with HSTs having
only one power car. When it came to the number of HST sets cleared for use on third rail routes, the InterCity Director could not be precise because of vehicles moving between sets, but estimated around 33 to 35.
The next hiccup came when the Parcels Sector Director weighed in to remind his colleagues about his Sector’s requirements, and that the overall cost to BR of the HST cascade should not rise because additional trains were needed for parcels and mail traffic.
Irritation began to mount over the attitude of the Provincial Director, who caused a delay by failing to supply information and taking a unilateral stance on the status of Clifton Depot ( York). The Director was also considering a new design of DMU for the North TransPennine routes, although a superior standard of rolling stock was still envisaged for the principal Liverpool to Newcastle workings.
Meanwhile, the engineers busied themselves with producing costings for various modifications to HST vehicles. These included modifying First Class vehicles into Standard or brake vans for parcels traffic, while re-gearing for 100mph was put at £ 50,000 per power car. Costs also had to be worked up for alternative locomotive-hauled rakes, where the traction might be either a refurbished Class 47 or the proposed Class 48s.
Towards the end of 1985, work carried out by the Research Department had established that a version of the Class 150 outer suburban DMU could be built at a lower cost (and with a superior power/weight ratio) than the Class 210 option. It would have vehicles of 23 metres in length, underfloor engines, and be capable of 90mph-100mph.
Paddington to Oxford, Worcester, Hereford and Birmingham services were envisaged as the first recipients. Thereafter, any journey exceeding 50 miles was regarded as suitable for the new trainset. The North TransPennine and internal Scottish routes were also potential recipients.
All three of the passenger business sectors supported the development of this new DMU, which emerged as the Class 158. That meant implications for the HST cascade because, for example, LSE was no longer interested in these sets for its Waterloo to Exeter route.
Reviews of planned post-electrification services and a tightening-up in diagramming meant that by the start of 1986, only 32 sets were now envisaged to be released. Just why a tightening-up did not increase the number was not explained. Use on the ‘European’ and between the North and Dover was judged not to be profitable, while some cross-country and surviving locomotive-hauled trains on the Western Region were not viewed as long term. InterCity had identified a number of options: Strengthening WR internal services. North West/North East to Cardiff, Poole and Brighton.
Edinburgh to Sheffield via both the West and East Coast. Midland Main Line locomotive-hauled. Services still in play for LSE were those from Paddington to Oxford and onwards to Hereford. Meanwhile, Provincial was still contemplating two return Liverpool to Newcastle diagrams for the principal business workings (a continuation of a policy dating from 1960), and for Edinburgh to Aberdeen/ Inverness and Glasgow to Inverness.
Even if all these proposals came to fruition, there would be a surplus of power cars, First Class and catering vehicles.
Remarkably, a top-level meeting in February 1986, chaired by the Managing Director (Railways), poured cold water on the work done to date. It didn’t see any urgency in identifying depot redeployments, and said InterCity would be stuck with sets not required by the other passenger businesses. This all happened against a backdrop of the Director of Projects remaining accountable for the £ 20m included in the ECML electrification for HST residual value.
Following this meeting, the Policy Director disclosed that the cost:benefit exercise under way for the North TransPennine services had
brought to light inconsistencies in reported HST costs. The Director pointed out that changes in maintenance practices, such as component exchange at depot rather than main works overhauls, would reduce costs from those prevailing currently. Moreover, operation at 100mph must bring lower costs than at 125mph.
The Director of Financial Planning then weighed into the debate. He reminded his colleagues of the £ 20m contribution to be derived from the HST cascade, and that the BR Board and Department of Transport would expect to see how this was to be achieved.
A new option came into play during September 1986, with consideration of the hauling of HST trailers by electric locomotives. One application considered was to use new Class 91s as part of a proving exercise for the design, while the Great Eastern Main Line (in conjunction with Class 86s) was seen as a long-term option.
While hauled Mk 3 vehicles had the same 850V DC electrics as Mk 1 and Mk 2 stock, Mk 3s in HST sets had a different threephase system. This made the latter unable to be supplied by a locomotive, and so various options were considered for dealing with this (all of which incurred a cost to a greater or lesser degree). Removing the traction equipment from a power car also incurred costs for modification, because ballast weights had to be fitted to keep the overall vehicle weight the same.
Another option permitting HST cars to be used other than as an HST was the fitting of a derated Paxman engine in a power car, purely to generate an electric train supply.
While this was about 25% cheaper than a new Driving Van Trailer (DVT) fitted with an inverter, it would introduce diesel fumes into otherwise electric-only terminal stations. Moreover, if the power car’s engine failed (estimated at twice annually per vehicle), on-train electricity could only be restored by attaching a replacement power car and not a locomotive with standard 850V train supply.
InterCity also ran a project to look at the feasibility of using 1+ 5 sets (one power car and five trailers) on cross-country services. This also ran up against the problem that failure of the single power car would not only cripple the train, it would also cut the supply for lighting and ventilation.
None of the modification options looked attractive financially. The additional weight of a power car over a DVT was estimated to cost 1p per mile in extra fuel. Fitting an inverter in place of an engine came out at a staggering £ 200,000. A power car had insufficient parcelscarrying capacity, and this would necessitate altering its interior. While the modified power car option was costed as the cheapest option, the availability of DVTs and cascaded DBSOs from ScotRail push-pull services led to the decision not to use the redundant power cars as train supply units.
The proposal for endurance-testing newly commissioned Class 91s by the haulage of HST sets between King’s Cross and Leeds was implemented from spring 1988. One Class 43 was detached, and the other had a nose end buffer beam fitted.
Other modifications included the fitting of equipment to permit the power car to become a DVT, capable of operating the ‘91’ in pushpull mode. The Paxman engine supplied electricity for the train, but not traction. However, such a light loading on the diesel caused problems, and a further modification restored traction capability, which then offered up to 8,000hp in conjunction with the ‘91’.
With ECML electrification completed by 1991, InterCity decided to retain some HSTs on the route for services extended north of Edinburgh to Aberdeen and Inverness, and also to Glasgow. With no interest from the other passenger businesses in acquiring displaced sets, InterCity found the best fit for its service network that did not involve costly modifications in line with those proposed above.
The sector still operated a number of trains using Class 47 traction, and the aim was to substitute HSTs for these where displaced sets permitted. This was particularly the case on Scotland to the South West routes, but also applied on Western Region internal diagrams.
Not only did the WR eliminate locomotive haulage where possible, cascaded Trailer Second Open vehicles were used to strengthen seven-car sets to eight coaches. A novel innovation was the substitution of HSTs for hauled rakes between Euston and Holyhead.
Electrification and Sectorisation also had an impact on depot allocations. Bounds Green and Heaton lost their allocations, while Craigentinny became responsible for most of the cross-country fleet. Neville Hill retained the allocation for ECML turns and those for the Midland Main Line. Eventually Old Oak Common lost its sets to Laira.
There is no record of whether the redeployment achieved the £ 20m value ascribed to the displaced HSTs in the ECML electrification appraisal. The evolving debate over three years highlights the state of flux in which the railways operated in the postSectorisation era, and how the business units (rather than the Regions) prioritised their own requirements.