TGR K class

The vehicles of the class K of the Tasmanian Government Railways were Garratt steam locomotives for 610 mm gauge. It was the first Garratt locomotives ever and one of only two Garratt series with composite engine. One of the locomotives - or more precisely a combination of parts of both locomotives - has been preserved and is now on the Welsh Highland Railway in regular operational use.

History

The first Garratt locomotive

Herbert William Garratt, the inventor of this design principle, campaigned in 1907 for a manufacturer who was interested in his idea. At this time, Beyer- Peacock lay before a request for a locomotive that was at the North - East Dundas Tramway in Tasmania replace the engine of the type used there Hagans ( class J), which was very prone to failure because of their complicated lever mechanism. Beyer Peacock Garratt to put ideas and delivered in 1909 two machines to Tasmania.

The North - East Dundas Tramway led over a distance of 27.3 km from Williams Ford in the mining town of Zeehan, a hilly track with tight curves. The two Garratts proven and remained until the cessation of the track in 1930 in use. Subsequently, they were parked in a shed in Zeehan.

Saved by Beyer- Peacock

1947 Beyer Peacock bought back one of the most historically significant locomotives and brought them to England. This machine consisted of the better-preserved parts of the two original machines. The drive bogies come from the K1, boiler and bridge frame of the K2. The remaining parts were sold as scrap.

The locomotive was exhibited at the factory by Beyer - Peacock. After plant closure in 1965 the machine from the Ffestiniog Railway was purchased with the intent to take it again. For a time the locomotive was exhibited at the station of Porthmadog. The narrow gauge railway that would have required extensive modifications to the engine, and therefore was abandoned on a tag and handed the machine to the National Railway Museum in York.

Restoration by the WHR

The rebuilt from the Ffestiniog Railway Welsh Highland Railway has a narrow section less than the actual Ffestiniog Railway, and the K1 could be used in their original form there. In 1995 the locomotive was taken out of the museum and first issued as an advertisement for the WHR in different places. Subsequently, the restoration of the machine began. Among other things, a new boiler was built because the old one had been found to be beyond repair.

Because of the new boiler is now only the bridge frame a part of the K2. The locomotive is therefore designated by K1 but bears number plates of both locomotives to document this condition.

The locomotive was initially equipped with a oil burning, as it was customary in the FR / WHR, and has also made ​​its first test drives in this state as of 2004. Because of the higher oil price but it was built back to coal firing in early 2007. The first "official" use took place on 19 October 2007.

The K1 has the highest axle load of all locomotives used on the WHR, and therefore the machine mastered tensile loads, while not come close to that of the 2 × 3 -link couplings South African Garratt class NGG 16, but for all used in practice trains the WHR is sufficient.

Technology

The locomotives of the class K are different in one respect from all later built Garratts: The cylinders are located on the inside of the motor bogies, ie below the bridge frame. Because this already at this relatively small machine leads to structural constraints and example the characteristic bent over the cylinders bridge frame requires, this design was not repeated despite the advantage of shorter steam lines - with the exception of two in 1994 and 2006 built locomotives for the Ferrocarril Austral Fueguino, but in their design for a scaled-down replica of the class K go back. Another problem with this cylinder arrangement was that the cab because of the immediately underlying cylinder heated up more than usual.

Because of the inside cylinder results in a weight distribution that allows the arrangement of the pivot exactly between the axles of a bogie ( see drawing). For all other Garratts the pivots are significantly shifted toward Lokomotiv center.

Another unusual and only one other Garratt repeated ( locomotive No. 208 of the Burma Railways ) is the composite engine. The high-pressure cylinders are located at the rear motor bogie, front the low-pressure cylinder on. Both trucks are directly connected to each other by a horizontal steam pipe - a benefit of the inner cylinder.

Both trucks have the outer frame and the control corresponds to the type Walschaerts / Heusinger. Both high-and low-pressure cylinders are equipped with piston valves.