Freight operator GB Railfreight (GBRf) is modifying 12 of its Class 66s with different gear ratios to enable them to increase their power output.

The regearing is to provide suitable motive power for an increase in demand for locomotives suitable for hauling heavy trainloads.

Modifying the gearing of the locomotives will change the gear wheels between their traction motors and axles to provide a greater torque and better acceleration, giving them the ability to haul heavier loads more efficiently. The conversion will also see the maximum speed of the modified Class 66s reduced from 75 mph to 65 mph.

Four locomotives have already been modified, Nos. 66793-66796, which are allocated to the pool and were imported from Europe in 2020/21. The fifth locomotive to be modified was No. 66779 Evening Star, which was the last Class 66 built for the UK and has now been renumbered 66689.

The next Class 66s to be modified are Nos. 66757, 66772, and 66777. After conversion, they will be renumbered 66667, 66682, and 66687. The four original locomotives that were regeared, Nos. 66793-66796 will also be renumbered at a later date. GBRf Class 66s in the range 66752-66777 are also being considered for conversion with modified gear ratios, and would be renumbered 66662-66688 once they have been modified.

GB Railfreight’s decision to modify some of its Class 66s follows similar modifications carried out last year by DB Cargo when ten locomotives were regeared so that its older and less reliable fleet of Class 60s could be retired.

It is expected GB Railfreight’s gold liveried Class 66 No. 66301 and an IIA-D Biomass Hopper, also in gold livery, will attend this August’s ‘Greatest Gathering’ at Alstom‘s Litchurch Lane Works in Derby. The gold livery was specially applied to celebrate 50 years of serving Drax Power Station.

“Our fleet must meet the needs of our customers. This regearing programme will ensure that we have the right kit to deliver efficient logistics solutions in support of construction projects across the country.”

“Liam Day, Asset Director at GB Railfreight