The mixed-traffic ac traction units will replace SRT’s ageing fleet of 48 GE UM12C locomotives, which were built between 1963 and 1966.

According to the tender documents, SRT requires 177 locomotives for service each day, although availability at present rarely exceeds 144 locomotives per day.

The first two locomotives must be delivered within 18 months of contract signing. Delivery of the remaining 48 units must be completed within 30 months of contract signing.

The 120km/h locomotives will have a maximum axleload of 16 tonnes and a minimum nominal rating of 2.24MW.

SRT has set a budget of Baht 6.24bn ($US 179.6m) for the procurement.