What is the default maximum speed for turnouts that do not have speed signs?

The default maximum speed for turnouts that do not have speed signs is indeed 25 km/h. This is based on standard practices within New South Wales rail operations regarding safety and effective train handling.

The speed limit for turnouts is set to ensure that the transition between mainline tracks and diverging tracks occurs safely. Turnouts, which are used to guide trains from one track to another, are designed with certain geometrical properties that impact how trains can safely navigate without risking derailment or excessive wear on the rail infrastructure.

The designation of 25 km/h serves as a benchmark to ensure both the safety of passengers and the integrity of the railway system. By adhering to this maximum speed where no speed signs are present, railway operators can manage risks effectively and maintain a safe operating environment.

In contrast, the other options listed might not meet safety standards or operational guidelines, which is why they are not the default maximum speed for turnouts.