USA: Union Pacific and Wabtec have announced a ‘landmark’ $1·2bn agreement for the modernisation of the railway’s AC4400 diesel locomotives to extend their lives, increase fleet standardisation and take advantage of next generation control and diagnostics technologies.
Each loco will receive the FDL Advantage engine upgrade for enhanced fuel savings, Locotrol Expanded Architecture to support the safe and efficient operation of longer trains and a new modular control architecture offering ‘next-generation’ data, diagnostics and software capabilities.
The upgraded locomotives are expected to offer a 14% increase in tractive effort and reduce fuel consumption by more than 5%,; there will also be an 80% improvement in reliability.
‘These redesigned locomotives will be just like new, providing the improved fuel efficiency and enhanced reliability that we need to grow with our customers and to win new business’, said Union Pacific CEO Jim Vena on February 4.
The work is to be undertaken at Wabtec’s US facilities, with deliveries starting from 2027. The agreement signed in the fourth quarter of 2025 is Wabtec’s fourth major modernisation contract from Union Pacific since 2018; it follows on from a 2022 order due to be completed later this year.
The railway says that once the latest contract has been completed it will have more than 1 700 modernised locomotives in its fleet.
