These tank engines were designed at the end of World War 2 to cater for growing Brisbane suburban traffic. They were an improved version of the earlier D17 Class incorporating many modern features including roller bearings, longer travel valves and self-cleaning smokeboxes. The design took full advantage of the loading gauge to provide a slightly larger boiler together with increased coal and water capacity. Higher boiler pressure and increased piston stroke made the new engines more powerful than their predecessors. An unusual feature of the locomotives, for QR at least, was that the top of the chimney was lower than the height of the cab roof. Approval was granted for Ipswich Workshops to construct six engines, but post war material shortages and heavy maintenance programme delayed the delivery of the first of these until 1948. By this time, increasing traffic caused the size of the order to be doubled. Their introduction allowed the last of the aging saturated D16 class tank engines to be retired and several of the D17 Class at Mayne to be transferred to Wooloongabba.

All engines were attached to Mayne depot and, like their predecessors, were restricted to the Brisbane suburban area bounded by Grandchester, Ferny Grove, Pinkenba, Shorncliffe, Petrie, Kingston and Lota. Initially they were used exclusively on the Northside suburban passenger and a few local goods trains in the ‘off peak’ periods. With full tanks the engines had a good factor of adhesion and were capable of rapid acceleration away from stations. They were able to haul an eight-car stopping passenger train between Central and Ipswich without taking water en route. This feat was beyond the capacity of the slightly less powerful D17s and so enabled some tender engines to be released for long distance country trains. In later years, tender engines resumed working these and other longer suburban runs and the DD17s took over from the older D17 engines on trains to intermediate termini where there were no turning facilities. Increasing numbers of 1720 Class DEL saw them eliminated from these passenger workings in August 1967. After the closure of Wooloongabba depot in September 1967, several made appearances on the Southside passenger trains until the dieselization of those services later the following year.

Between 1953 and 1956 the class suffered a number of embarrassing failures in traffic due to broken driving axles and fractured coupling rods. Fortunately, none of these incidents resulted in seriously consequences. The defect was overcome with fitting of “Vibroc” steel axles and altering the horn cheeks. After these alterations, they then established a reputation for reliable service that was not surpassed until they were replaced by diesels.

Prototype N°949 was painted black when it entered service on 17th December 1948. The second engine, N°950 was the 200th locomotive constructed at Ipswich Shops and was exhibited at the first Queensland Industries Fair in May 1949. It was painted in a dark Royal blue livery with red and silver trim. The engine was kept in steam during the display with its wheels mounted slightly above the rails so as they could rotate. When N°951 – N°954 were completed later that year, they also appeared in the same colour scheme. N°949 was similarly repainted in October 1949.

The second batch (N°1046 – N°1051) were constructed between 1950 and 1952. N°1051 was not only the last of the class but also the last locomotive to be constructed by Ipswich Workshops and it entered service on 3rd July 1952. This batch of engines was painted “Midway” blue; a colour midway between Royal and sky blue. The first six were later similarly repainted. This colour scheme earned them the nick name “Blue Babies”.

N°1048 was the first member of the class to be withdrawn and was written off in November 1966. N°952 and N°953 followed in 1967 with a further seven engines in 1968. N°1046 and N°1049 survived until the following year.

Four members of the class survive today. N°1046, N°1047 and N°1049 were sold to Zig Zag Railway. N°1051 was retained by QR. It was overhauled and restored to working order by Ipswich Workshops in August 1993


  • Wheel arrangement


  • Cylinders (diameter X stroke) ins. (4)

    17 X 24

  • Rigid Wheel Base


  • Length over Buffers


  • Coupled Wheels diameter ins.


  • Axle Load


  • Boiler Pressure psi


  • Heating Surface of tubes - sq feet


  • Heating Surface total - sq feet


  • Grate area - sq feet


  • Weight - adhesive - tons


  • Weight Engine


  • Coal capacity - tons


  • Tractive Effort - lbs. (85%)


  • Factor of Adhesion


  • Valve Gear


  • WH Pump

    10 X 10⅝

  • Brake Valve


Zig Zag Railway

DD17 N°1046

This was the first engine of the second batch of the class to be built and the 205th locomotive constructed at Ipswich Workshops. It cost ₤22,403/17/5 ($1,223,123.33 in today’s values) and commenced to run on 3rd August 1950. The engine had an uneventful career in suburban service except for two incidents in the latter part of 1953. On 24th August, it suffered a broken coupling rod at Strathpine and less than three months later, on 10th December, fractured the right-side guide bar and bent its piston rod at Booval.

Brisbane suburban services consisted of two brief ‘peak’ periods per weekday with a limited number of trains at other times. Altogether, approximately forty engines were required to cover the rush hours but many of those had little or no work available for the remainder of the day. Despite this anomaly, the engine regularly achieved over 4000 miles (6438km) per month during its first decade when the class worked many of the longer Ipswich runs and weekend services. By 1960, increasing numbers of diesels gradually started making inroads on suburban workings and also released tender engines from country work to take over most Ipswich and Petrie trains.

Engine N°1046 paid ten visits to Ipswich Workshops during its career with the final one occurring in January 1967. She was last used in December the following year and was then withdrawn from service having run a total of 433,430 miles (697,638km).

DD17 N°1047

This was the 206th engine constructed by Ipswich Workshops and was completed at a cost of ₤22,403/17/5 ($1,223,123.33 in today’s values). The engine entered service on 29th June 1951 and like other members of the class was attached to Mayne depot. The engine suffered two broken axles during her career. The first occurred at Bowen Hills on 10th February 1954 and a little over two years later on the 30th August 1956 another at Brunswick Street, less than a mile away from the site of the first incident. The only other mishap took place at Oxley on 2nd January 1957 when a trailing coupling rod was bent due to a knuckle pin defect.
The highlight of the engine’s career came on 2nd October 1966 when it hauled an ARHS excursion from Brisbane to Toowoomba and return. This was the first occasion that a member of the class had worked outside the Brisbane suburban area. Due to its limited coal and water capacity, stops were required at almost every available water hydrant and the bunker was re-coaled by hand at Helidon.

By that time, the introduction of the 1720 Class DEL began sounding the death knell for steam on suburban passenger trains and tank engines were eliminated from northside services in August 1967. However, several members of the class, including N°1047, were then utilized to replace the aging D17 engines on southside trains until they too were dieselized the following year.

Engine N°1047 visited Ipswich Workshops on eleven occasions during its career with the final occasion being in September 1966. The engine last ran in January 1968 and had achieved a total mileage of 453,092 (729,181km).

DD17 N°1049

This was the 208th engine built by Ipswich Workshops and entered service on 13th December 1951. The cost of construction was ₤22,403/17/5 ($1,223,123.33 in today’s values). The engine was used at various times to test a number of items of equipment. It entered service with a Davies and Metcalfe mechanical lubricator in lieu of the standard Nathan type. A Davies and Metcalfe brake valve was fitted for trial purposes in March 1956. This evidently was not entirely successful as the engine subsequently failed thrice in traffic due to rotary valve defects. A Smith-Stone speedometer was also attached at the same time for test purposes. It proved a success and was subsequently removed and fitted to Beyer Garratt N°1102. The latter type of engines was the only QR steam locomotives to be permanently fitted with such devices.

The engine was involved in one major incident during its career when on 30th July 1954 it sustained damage after being struck by DEL 1208 in Mayne yard. This resulted in one of the eleven visits the engine had to Ipswich Workshops during its career. The last such occasion was for a Partial Overhaul in November 1966.

Like other members of the class, it received heavy use in the earlier part of its career but increasing numbers of diesels saw it placed in temporary store at Mayne on 25th November 1966. It was returned to traffic in September the following year. Engine N°1049 was the last used in December 1968 and ran a total of 400,498 miles (644,540km) during its relatively short 17-year career.

Other Locomotives

10 Class

10 Class Diesel Hydraulic Locomotives

AC16 C16 Tender

AC16 Class Locomotives

BB18 Class Locomotives

BB18¼ Class Locomotives

Beyer Garratt Locomotives

C17 Locomotive

C17 Class Locomotives


DD17 Class Locomotives