Born from the ashes of mighty steam powered mining equipment, forged in sheer determination and assembled with one thing in mind, moving ore as fast and as cheap as possible. The M5 class 2-10-6 stands as a testament to the rough hard working people who built her.

The Carbon Alloy boilered 3 cylinder 390 psi 70 inch driver equipped M5 produced a tractive effort of 421,377 pounds. Unheard of in any rigid frame locomotive any where in the world. Comparable with legendary loco types of, US and British design the M5 was and is a monument of what it took to extract ore from the harsh environment of the rugged Great Dividing Range and move it to market.

As ore not coal was in major abundance class C or commonly known as Bunker C fuel oil was used as the primary fuel for this giant. With a common ore train being 320 cars long and a 3% ruling grade on the Flinders Division over the Great Dividing Range it took brute force to make the journey in a profitable way. Maybe not as a design spec. Or maybe the builders desire to do this with class the M5 accomplished this task daily with strength and determination and is viewed by many as poetry in motion.

The length of the journey from mine to port was close to 2000km, pulling a 320 car ore train this is a daunting task to say the least. Although very capable of accomplishing this they were often double headed to increase speed and overall turn around time. The M5 was also used in Townsville to assist the tugs in positioning the humungous ore freighters into position for loading .It was not an uncommon sight to see a M5 pulling a ship into dock while small tugs pushed from the water. Many an engineer boasted that a pair of M5s could pull the whole mine to port if need be. Once in their first year of service a pair of M5s pulled 456 loaded ore cars from the mine in MT Isa to the port in Townsville in a record 21 hours. This included several water stops and once to top of the fuel. Considering the loco could achieve 180kmh and the grades of GT Summit this record has hardly been challenged even with today’s massive power.

The M5s were more than any 2-10-4 could be and they had fireboxes comparable to that of the Northern Pacific Yellowstones. The main feature of the M5 was that it was flexible. During the phasing in of electrical air-conditioning on the Broken Arrower the M5ps were refitted with a steam turbine in the tender which drove a generator delivering power to the train. This flexibility could also be found on M5es, the largest of the M5s, where the M5es were fitted with a set of diesel locomotive controls in the rear of the cab so that the M5es could operate with early diesel locomotives, the M5es dominated over the early GDRMB diesels which were their only competitors. The M5s were steam locomotives out to show the world that articulation is not the only way of delivering power to the rails.

The M5’s successor could only be the locomotive that shared the same nickname as the big black and silver ore haulers of the north-east. These locomotives came from GDRMB just like the M5s of now 45 years ago the new GT5M continues in the legacy of the worlds biggest rigid frame locomotive and worlds most powerful locomotive. The big black and silver ore haulers of the north-east live on in these new cutting edge locomotives.

The M5 truly lived up to and surpassed the expectations of the builders and most of all the CT,MtI&C. The M5s could only be summed up in two words, ‘gargantuantly massive’. May the soles of the M5s be carried on in the new modern GT5Ms and confirm to the world that the M5 has no equal.


By Terry Powell and Mitchell Legg