Tarcoola, at the 504.5 km, looking east along the Trans Australian Railway in the middle of the yard, the Central Australian Railway is on the left, loop on the right, east leg of triangle is just in view with the sidings running east behind the large tree and water tank. Tarcoola is the junction for the TAR and CAR railways situated 504 km from the 0 km datum at Coonamia. GeoData location. 15th April 2003.