This backshunt and the scissors crossing were part of the sidings installed for the coal mining and were removed after it closed.
1982 historical view of the station. Showing that the loop and siding remained the same size as they were in 1923. The original shorter loop was extended in time for the opening of the Otira Tunnel as it was the case that many of the facilities in various places in the Midland Line, such as the Springfield deviation, were improved in time for the opening of the full route.
Looking at the route of the tramway that was installed for the coal mine. The section just above Avoca station was an incline worked by endless rope haulage to bring the coal tubs down to unloading. Whereas the main part of the route going across the map from left to right was worked by a small steam locomotive.
There was another incline to bring the empty coal tubs down into the Broken River bed to reach the coal mines. A large steam boiler was located at the top of this incline to work the haulage rope that took the empty tubs down and brought the full ones up.
The larger part of the coal mine was on the south side of Broken River. Within the area shown there were two distinct sections of mining, each accessed by its own tramway crossing the river. The earlier and larger section was to the right and the later and smaller section to the left, probably as a new exploration after the main mine caught fire.
Another area that was mined was on the north side of Broken River reached by an extension of the tramway that ran along the riverbank. This appears to be an earlier part of the mine. The mining company was in operation in total for ten years, from 1918 to 1928 (a note on one of the plans shows the date April 1928 "Mine Abandoned").