TGR class K
| TGR class K | |
|---|---|
 Factory photo of the K1
|
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| Numbering: | K1 and K2 |
| Number: | 2 |
| Manufacturer: | Beyer-Peacock |
| Year of construction (s): | 1908 |
| Type : | B'B 'n4v (Garratt) |
| Gauge : | 610 mm |
| Service mass: | 33.4 t |
| Friction mass: | 33.4 t |
| Wheel set mass : | 8.9 t |
| Driving wheel diameter: | 800 mm |
| HD cylinder diameter: | 280 mm |
| LP cylinder diameter: | 432 mm |
| Piston stroke: | 406 mm |
| Boiler overpressure: | 134 N / cm² |
| Grate area: | 1.37 m² |
| Radiant heating surface: | 5.57 m² |
| Tubular heating surface: | 52.7 m² |
The class K vehicles of the Tasmanian Government Railways were Garratt steam locomotives for 610 mm narrow gauge . They were the very first Garratt locomotives and one of only two Garratt series with compound engines . One of the locomotives - more precisely a combination of parts of both locomotives - has been preserved and is now in regular service on the Welsh Highland Railway .
history
The first Garratt locomotive
Herbert William Garratt , the inventor of this construction principle, began advertising in 1907 for a manufacturer who was interested in his idea. At that time, Beyer-Peacock received a request for a locomotive that could replace the Hagans ( class J ) machine on the North-East Dundas Tramway in Tasmania , which was very prone to failure due to its complicated lever mechanism. Beyer-Peacock implemented Garratt's ideas and delivered two machines to Tasmania in 1909.
The North-East Dundas Tramway ran over a distance of 17 miles from Williamsford to the mining town of Zeehan , a hilly route with tight curve radii. The two Garratts proved their worth and remained in service until the line was closed in 1930. They were then placed in a shed in Zeehan.
Rescue by Beyer-Peacock
In 1947 Beyer-Peacock bought back one of the historically valuable locomotives and brought it to England. This machine consisted of the better preserved parts of the two original machines. The drive bogies come from the K1, the boiler and bridge frame from the K2. The remaining parts were sold as scrap.
The locomotive was exhibited in the Beyer-Peacock factory. After the plant closed in 1965, the machine was bought by the Ffestiniog Railway with the intention of putting it back into service. For a while the locomotive was on display at Porthmadog station . However, the narrow clearance profile of this railway would have required extensive changes to the locomotive, and therefore one did without a conversion and handed the machine over to the National Railway Museum in York .
Restoration by the WHR
The Welsh Highland Railway , rebuilt by the Ffestiniog Railway, has a less narrow profile than the actual Ffestiniog Railway, and the K1 could be used there in its original form. In 1995 the locomotive was taken from the museum and initially exhibited in various locations as an advertisement for the WHR. Then the restoration of the machine began. Among other things, a new boiler was built because the old one had proven beyond repair.
Because of the new boiler, only the bridge frame is now part of the K2. The locomotive is therefore designated as K1, but has license plates from both locomotives to document this condition.
The locomotive was initially equipped with an oil furnace, as was customary at FR / WHR, and in this condition it also made its first test runs from 2004. However, due to the increased oil price , it was converted back to coal-fired at the beginning of 2007. The first "official" mission took place on October 19, 2007.
The K1 has the highest axle load of all the locomotives used on the WHR, and the machine therefore handles train loads that do not come close to those of the 2 × 3-fold coupled South African Garratts of the NGG 16 class , but for all of the WHR trains used in practice is sufficient.
technology
Class K locomotives differ from all Garratts built later in one point: The cylinders are on the inside of the motor bogies, i.e. under the bridge frame. Because this already leads to structural constraints in this relatively small machine and z. B. requires the characteristic bridge frame cranked over the cylinders, this design was not repeated despite the advantage of shorter steam lines - with the exception of two locomotives built in 1994 and 2006 for the Ferrocarril Austral Fueguino , which, however, are based on a scaled-down replica of the Class K go back. Another problem with this cylinder arrangement was that the cab heated up more than usual because of the cylinders immediately below.
The internal cylinders result in a weight distribution that enables the pivot pins to be positioned precisely between the axles of a bogie (see drawing). On all other Garratts, the pivot pins are clearly shifted towards the center of the locomotive.
Another unusual feature, and only repeated on one other Garratt (locomotive No. 208 of the Burma Railways ), is the compound drive . The high pressure cylinders are located on the rear motor bogie, the low pressure cylinders on the front. Both bogies are directly connected to each other by a horizontal steam pipe - an advantage of the internal cylinders.
Both bogies have external frames and the controls correspond to the Walschaerts / Heusinger design. Both high and low pressure cylinders are equipped with piston valves.
literature
- AE Durrant: Garratt locomotives of the world . Birkhäuser Verlag ISBN 3-7643-1481-8
- Richard L. Hills: The Origins of the Garratt Locomotive . Plateway Press, East Harling, 2000, ISBN 1-871980-43-7
Individual evidence
- ↑ Photograph of the K1 in Porthmadog train station (1966) ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.
