Casino. Bruxner Highway perhaps just west of town.
Yep - it's Black Gully bridge about 2 miles west of Casino.
According to the August 1940 edition of Main Roads
Black Gully Bridge at 1 mile west of Casino has been constructed on piers erected by the Railway Department when the Casino-Bonalbo railway works were in progress
Interestingly, when the reconstruction of the Casino-Tabulam section of what is now Bruxner Highway was being planned in the 1930s, consideration was given to utilising the railway formation for the first 10 miles or so. However, the cost of widening the cuttings was prohibitive and the existing road alignment was generally adhered to.
Over to you 5915.