Mixed trains initially ran four times a week and were replaced in 1929 by a daily rail motor service to Toowoomba. The line connected the small towns of
Acland,
Kulpi,
Peranga,
Narko,
Nutgrove,
Wutul and
Cooyar to the
Queensland Rail western line at
Oakey until 1964. This provided passenger and farm produce services not only to these towns but also to the surrounding townships of
Quinalow,
Maclagan and
Evergreen. Coal was transported between Acland and Oakey, this portion of the branch line remained in service until 1969. A similar parallel branch line existed connected
Haden to the Western Line at
Kingsthorpe from 1910 to 1964. As the competing service of
bullock carts gave way to
motor vehicles rail patronage declined resulting in both services becoming uneconomical to maintain. With negligible track remaining the Oakey-Cooyar branch line could all but be overlooked as a fading scar on the landscape, it retains its significance however through the still intact
Muntapa Tunnel. A feat of early
Queensland Railways engineering achievement, the Muntapa Tunnel remains the only
tunnel in Queensland to pass under the summit of Eastern Australia's
Great Dividing Range. This tunnel was constructed with manual labour. It is now home to a colony of bats. The Oakey-Cooyer branch line is also of early surveying significance. Rail engineering practice of the period avoided the construction of tunnels, so significant surveying was undertaken to avoid tunnelling and to minimise rail
gradients. The largest gradient of a line mandates a larger, more expensive loco or a de-rating of carrying capacity, both of which would result in a less economical service for the line as a whole. The Oakey-Cooyar branch line was repeatedly surveyed to arrive at its built route, which had a negligible gradient over its length, but which required the 300m tunnel. The low gradient required a devious route, particularly at Narko and adjacent to the tunnel. == References ==