After she discovers the two bodies Helen decides she doesn't want to get involved - she was just about to leave Reno for home anyway so she heads straight to the station for the late night train to San Francisco.
... from 1928 ... The Reno depot was built in 1925 by Southern Pacific. This postcard image shows the station three years after it went into service and it still looked like this in 1947 when the movie was filmed. The station fronts E. Commercial Row but this view, from Lake Street, of the rear track-facing side of the building shows us where the following scene was filmed (map).
... and Now, because the depot is in the center of town the tracks have since been lowered and street-level bridges built to alleviate traffic-crossing problems. The depot has been kept in its original form and the building is now on the National Register For Historic Places.
Then ... While Helen waits for the train (her luggage is on the left) who should walk up but Sam (the killer - we know it but she doesn't, yet). He too is making a hasty exit from the scene of the crime.
... and Now, the red border outlines the same part of the depot (CitySleuth must confess that he used the front exterior for these comparisons because 1) the rear is harder to photograph the matching shot due to the major changes resulting from lowering the track, and 2) the depot architecture is identical front and back.
Then ... They strike up a conversation, recalling their first meeting in the casino. Sam offers to carry her luggage onto the waiting train and she is quite happy to accept.
... and Now, the red border outlines the same part of the depot (again using the more accessible but identical front of the building).
... and Now, this recent photo taken track-side shows where the filming took place, on the left, before the tracks were lowered.
In the club car they waste no time flirting with each other as the train pulls out past the glitter of downtown Reno.
Then ... By the time they get on the ferry at Oakland Pier to complete the journey to San Francisco it's obvious they will continue to see each other. But wait a minute ... there's a continuity goof in this footage - with Yerba Buena Island on the left this is a view from San Francisco showing the ferry going in the wrong direction, cruising under the Bay Bridge from left to right towards Oakland.
Then ... But in the next shot their ferry is on the other side of the bridge and heading, correctly, towards San Francisco.
... and Now, six decades of development has transformed the San Francisco shoreline.