ScotRail Class 156 (Photo: Tony Miles)

UK: ScotRail is developing plans to withdraw all of its diesel trains as part of a programme to replace 65% of its fleet in 2027-35.

The fleet renewal plans involves replacing around 675 vehicles of various types as their leases expire and it becomes uneconomical to extend their lives, with consolidation on five types of train.

ScotRail’s diesel trains, which currently comprise HST sets and Class 153, 156, 158 and 170 diesel multiple-units, would be replaced with vehicles powered by overhead electrification where viable, and batteries or hydrogen elsewhere. The aim is to eliminate carbon emissions from passenger operations, and to offer improved comfort, accessibility and reliability, as well as to cut operating costs.

Procurement plan

Three procurement competitions are planned.

Phase 1 in 2022-23 would cover the procurement of suburban electric and battery-electric multiple-units. These would enter service in 2027-30 on services around Edinburgh, Glasgow, Perth, Dundee and Aberdeen. The suburban procurement is envisaged to cover around 120 trainsets totalling about 550 vehicles, with a minimum order for 64 units and 295 vehicles.

Phase 2 of the procurement is planned for 2024-25 and would see new trains ordered for rural routes.

Phase 3 in 2025-26 would cover inter-city trains to connect Edinburgh and Glasgow with Aberdeen and Inverness.


Bidders would be required to submit options for both a Technical Services Agreement and Technical Support & Spares Supply Agreement, with a decision which provides best overall value to be taken prior to contract award.

As well as meeting customer, technical and operational requirements the trains would be required to provide value for money when looking beyond the capital and operating costs and including economic and societal benefits and minimising the environmental impact.

A separate parallel procurement would be held to identify a suitable financier.

Associated upgrades to maintenance depots and servicing facilities are likely to be delivered by Network Rail, although ScotRail will investigate whether there would be any benefit in this work being delivered by the train manufacturer and maintainer.

Procurement of the trains will be undertaken by ScotRail Trains, the arm’s length operator which is owned by Scottish Rail Holdings, a non-departmental public body controlled by Scottish ministers.

SRT has invited expressions of interest in providing contract management and legal support services during the procurement. This contract would start in October 2022 with the suburban train procurement, and would then move onto to the rural and inter-city orders. The legal services contract would run to March 31 2027, with an option to extend by an additional 36 months.