While the rollout of battery-electric buses (BEBs) has been slowed by the cost of building the charging infrastructure and availability of capable BEBs, Metro is upgrading and expanding its trolley bus network.
The current trolleys have only a small battery. That allows them to run briefly off-wire but not on steep hills. This helps in case of obstructions due to construction, accidents or events. During the Third Ave construction some routes (1, 3, 4, 7, 14, 36) have operated off-wire. During the Montlake construction Route 43 has operated off-wire. Once the trolley wire has been reinstalled, the routes will return to on-wire trolley operations.
Recently Metro started to upgrade the buses with larger batteries which will allow longer off-wire operations. They expect to upgrade all 174 trolleys by 2027. Metro is evaluating whether the upgraded batteries would allow Route 12 to operate off-wire until the overhead wire is completed on Pine St, currently scheduled for 2029. Metro is also considering trolley buses to operate off-wire for Route 48 until the gaps on the overhead wire are closed on 23rd Ave, currently scheduled for 2032. First it would need to improve power infrastructure though to accommodate the additional buses.
With the upgraded batteries and power systems, Metro hopes to run trolley buses throughout the week rather than powering the wires down for construction on Sundays.
PS: I updated this post as Metro contacted me to explain that the streetcar avoids the trolley wires by using its battery, not the other way around. Also, the current trolley batteries work uphill, but performance is poor making it unsustainable on steep grades.
