Puffing Billy Railway, Heritage railway in Dandenong Ranges, Australia.

The Puffing Billy Railway is a 762 millimeter narrow gauge line running from Belgrave to Gembrook through forested slopes and open valleys in the Dandenong Ranges. The route connects several stops and passes through areas of tree ferns, eucalyptus woodland and rural pastures.

The line opened in 1900 as one of five narrow gauge railways built to serve remote communities reliant on timber and farming. After closing in 1954 it was reopened by volunteers and has operated again with historic steam locomotives since the 1960s.

The nickname "Puffing Billy" comes from the puffing sound and whistle of the steam locomotives. Volunteers, many of them registered with the preservation society, staff the trains and maintain the engines. The railway keeps practices from the Victorian Railways era, such as the Staff and Ticket safeworking system, and its infrastructure is restored to reflect the line's heyday between 1900 and 1930.

Trains run daily between Belgrave and Lakeside, with Friday through Sunday service continuing to Gembrook. Open carriages let in wind and occasional ash, so layered clothing and closed shoes work best for the trip.

Passengers are allowed to sit on the open window sills of the carriages during the journey, dangling their legs outside the train. This practice was common on many rural railways in the past but is now permitted almost nowhere else.