Fantastic view, hadn't seen this, thank you!
This
old post references a photo of 490 with the herald scheme on the Sargent turntable on 8/14/40. Must be this shot in the Dorman collection:
RD119-004 (by the way, nice job by the Friends website, excellent improved photo interface).
By the time of the shot in your posting, the 490 had speed lettering, and a light show was covering the former turntable pit. I think it would have been in view just below/before the 490. Big changes over only a few months!