In mid-1974 the 10 SW900s were rounded up (two were on the NWP while the rest were part of the LA switcher pool) and hauled dead to Houston for upgrading to SW900E units at the Hardy Street shop. Your photo on a previous thread of the 1170 at the Homestead (West Oakland) was taken during the brief time it had been captured for use by the West Oakland Diesel Shop folks while it was moving from Eureka to Houston. Hardy Street had previously completed the NW2R and SW1200E programs, plus did a semi-upgrade on at least one (1105) SW8. Like the other classes, the SW900Es received mechanical and electrical upgrades, but unlike the others, the SW900Es received the SW1500-type headlight/signal light/class light packages shown in the photos. After rebuilding, they were generally less popular with crews than before because of the removal of various in-cab creature comforts.

The SW900s were intended for use as replacements for Alcos and FMs in the Bay Area. As they were released from Hardy Street, they moved dead to the Bay Area. Eight were initially assigned to the "Pool A" Bay Area switcher pool while the remaining two replaced the two SW900s that had been assigned to the NWP. As yard jobs dwindled and SW1500s could cover most of the remaining assignments, they mostly became spare units and tended to be stored at the Roseville shop. At least two worked (singly) on the Visalia Electric after the last Alcos were retired. The last of the SW900Es were retired in late 1986 and early 1987, and most were resold for service.