NZR G class (1928)

The 1928 -built vehicles of category G of the New Zealand National Railways (New Zealand Government Railways, NZR ) were steam type locomotives Garratt. They were the first and only Garratt locomotives that were used in New Zealand, and also the largest ever built in this country locomotives. However, they could not convince and were taken after a few years of his service. From the drive racks of three locomotives emerged in 1937 six conventional locomotives, which were also referred to as Class G.

History

After the New Zealand State Railways had already experimented with limited success with joint types of locomotives Fairlie and Mallet, 1928 three Garratt locomotives were purchased by Beyer - Peacock. You should reduce the pushing mode on the hilly routes of the North Island. The machines were given the class designation G, which had previously been worn by a number of 1873 -built tank locomotives (see NZR Class G ( 1873) ).

The Garratts were not a success, because they suffered from multiple problems that were only partly due to defects in the construction.

The couplings used in New Zealand were too weak for the trains that could pull the Garratt, and the railway station and sidings were too short. The Stoker jammed easily, the Garratt design was unusual for the maintenance personnel, and in New Zealand also unusual three-cylinder engine was hard to adjust. All this meant that the locomotives were retired in 1931 and thus one of the few Garratt locomotives, which proved unsuccessful.

In 1937 the parked locomotives were dismantled, and from parts of them came six Pacific locomotives ( further referred to as Class G ) and in particular the running and engines were re-used ( with the exception of the inner race axis ). These locomotives retained not only the class name but three of the six, the operating numbers of the Garratts. She also suffered from the problems of the retained when converting three-cylinder engine and were therefore discarded as early as 1956, as the first Hauptstreckenloks, had to give way to the rise of diesel locomotives.

The Garratts Class G were the only used in New Zealand locomotives of this type. There some Garratt were drafted for use on the Rimutaka steep ramp, of which, however, no one has come for execution. One of the designs was a locomotive for the fur system, another called for a speed reduction of the drive wheels in relation to the engine via gear transmission.

Technical Features

The locomotives had three-cylinder engines of the type Gresley, where the control of the inner cylinder was derived via transverse lever of the outer cylinder. Worldwide only one other Garratt was equipped with such engine, the locomotive of the LNER No 2395 (Class D1). The outer cylinders were inclined mounted so as not to violate the gauge. All cylinders were working on the central dome axis.

Unusual was the coal box, which was not based on the aft engine frame, but on the main frame. This facilitated the incorporation of the stoker, because there was no relative movements between the boiler and coal bin. The locomotives were thus an intermediate form between normal Garratts and the Union - Garrats, where also the rear water tank was mounted on the main frame (eg, class U of the South African Railways ).