Battery electric locomotives started becoming more popular in the early 2000s as switchers, but as the ongoing climate catastrophe intensified most of the class 1s in North America started showing interest in “what about a battery electric road locomotive” (cheaper than electrification if you’re primarily interested in them for PR purposes.)

Caterpillar subsidiary Progress Rail introduced one, Wabtec introduced one, so ILW’s board sighed heavily and directed the company to also build some demonstrator units.

The eco-646fb was what came out of this process in the middle of 2023; the front end & electrical subsystems of an eco-644-2 with a (Derby-built) battery compartment based on the class BS1 battery tender that had been operating on the M&B for the past 8 years. ILW built an eco-644-2 sled, then shipped it to the BAR shops where the battery compartment was fabricated and filled with high-capacity battery packs and a suitable large halon fire suppression system.

Painted in the ILW demonstrator scheme (a 99% copy of the Great Northern’s short-lived Big Sky Blue), it has been operating on the LT&L’s international line from Québec to New Brunswick since the start of July 2023.