The Sunset Limited – Back In The Day
Here’s a very rare view of Southern Pacific’s Sunset Limited during the 6-9 month period it operated with new Daylight painted diesels and older heavyweight passenger cars.
SP train #2 about to cross over Santa Fe tracks at Tower 32 in Beaumont, Texas in early 1950
When the Southern Pacific began to dieselize its passenger operations in the late 1940’s, Alco’s PA passenger diesel was the motive power of choice.
12 PA-1’s in the 6000 series were acquired for the Pacific lines in mid-1948. Another 12 PA-1’s arrived between June and August 1949 for its T&NO operations. These were numbered 200A,B – 205A,B
The Sunset Limited was operated with heavyweight equipment until mid-1950, at which time it was re-equipped with Budd streamlined trainsets.
The location of the photograph is quite interesting as well.
Tower 32 was the interlocking protecting the crossing between SP’s Sunset Route mainline and Santa Fe’s line into Beaumont. It was just west of the SP’s swivel bridge over the Neches River.
This stretch of SP trackage (the light purple broken line in the below image)) was abandoned in the 1960’s when the SP made a deal with the KCS to share the KCS Neches River lift bridge. The SP’s Neches River swivel bridge was then removed.
Southwest Rails 
FWIW, the last T&NO bridge over the Neches River in Beaumont was an American Bridge Company bascule span, wherein the counterweight is suspended out over the pivot end of the span and drops downward into the area above the track, rotating in a direction opposite that of the span. I can send a snapshot of it if you like. (I grew up in Beaumont.)
I’d love to see the bridge pic!