Yorkshire Dave
Western Thunderer
Although invented in the 19th century, it wasn't until after WW1 that dial phones started to be common. Railways were far from the early adopters. My mother worked a GWR plug board in the late 1940s.
A candlestick phone might be appropriate for the period.
I would suspect the increased use and availability dial telephones phones broadly mirrored the conversions from manual to automatic telephone exchanges where you no longer had to ask the operator to connect. If you called from a number serviced by an automatic exchange to a number serviced by a manual exchange the latter's operator would just connect the call without the caller asking to do so..
Railways probably had no need to adopt dial phones quickly as they effectively had their own internal telephone systems and exchanges not connected to the public network. They may have adopted dial phones in offices for their public network connections.