Prototype factfile: Class 69
Richard Clinnick writes…
The Class 56 fleet, built between 1976-84 in Romania, Crewe and Doncaster, had been nominated for a re-engineering programme by EWS in the late 1990s. The original Ruston-paxman power units were notoriously thirsty for fuel and, by the turn of the millennium, were beginning to show their age. These plans came to nought, however, as EWS opted to invest in an all-new fleet of 250 Class 66s. Having acquired a number of redundant Class 56s, why has the idea of a re-engineering programme been resurrected by GBRF, over 20 years later? Speaking to our sister title
RAIL in 2020, GBRF engineering director Bob Tiller explained how the plan to rebuild an initial ten
Class 56s was primarily based on a need to improve emissions, save costs through improved fuel economy and to encourage standardisation across its fleet.
Tiller also said that the conversion work is much more in-depth than when Brush Traction rebuilt Class 47s as ‘57s’, or the rebuild of ‘73s’ (which, along with fitting MTU engines to HST power cars, was also one of his projects). He explained: “The cooler group is from an EMD GT42AC locomotive, the alternator is from a metre gauge Gp-type locomotive and the electrical cubicle was specifically designed for the Class 69 project to fit within the Class 56 bodyshell.
“The cab interior is all new – the Brush controls have gone and it’s much more similar now to a ‘66’. We have kept the curved Class 47-style desk, but other than that it’s very Americanised. The front end has been redesigned and all the draughts have now gone.
“The ‘56’ bogies, wheelsets and traction motors have all been overhauled. One of the problems the ‘56s’ had was, when accelerating from a stand, the fourth powered wheel would invariably raise up and suffer wheel spin, due to weight shift. So we have fitted a better traction control system, which should make it more controllable.”
The cost of all this work remains lower than buying new locomotives. Also, there is currently nothing available that meets one of the main criteria – standardisation.
“We looked at ways of enhancing the GBRF fleet, but keeping as much standardisation with the Class 66 as possible,” said Tiller. Class 47s and ‘60s’ were also considered for re-engineering, but the ‘56s’ were available straight away. They were acquired from UK Rail, which had several examples stored at its Leicester depot.
“We looked at fitting a twin-engine Caterpillar design, an MTU V16 engine or even two Cummins engines, before settling on the EMD12N-710“said Tiller. These are what’s fitted in a Class 66”.
Despite the engines being new and compliant with current regulations, they are still of a design that had been discontinued. However, GBRF was able to prove that their emissions were an improvement on what had been in the locomotive previously. Furthermore, because the Class 56 retains grandfather rights on the network, the approval process was a lot quicker. Retaining the main structure, weights, bogies, motors and drawgear enables GBRF to retain the track dynamics and rail interface of a Class 56, and thus the project can be classified as an upgrade rather than an all-new design.
“These are a very clever design. We’ve been able to shoehorn everything into a UK locomotive, with the work carried out here in the UK,” said Tiller.