SLM HG 4/4
| SLM HG 4/4 | |
|---|---|
 Image of a HG 4/4 from the 1920s (SLM)
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| Numbering: | 701-709 |
| Number: | 9 |
| Manufacturer: | SLM |
| Year of construction (s): | 1923/24 (No. 701-705), 1929 (No. 706-707), 1930 (No. 708-709) |
| Retirement: | 1940s and 1975 |
| Type : | Dzz h2 (h4v) |
| Gauge : | 1000 mm ( meter gauge ) |
| Length over buffers: | 8950 mm |
| Height: | 3460 mm |
| Width: | 2650 mm |
| Total wheelbase: | 4440 mm |
| Empty mass: | 36.5 t |
| Service mass: | 45.9 t |
| Friction mass: | 45.9 t |
| Top speed: | 40 km / h (adhesion) 15 km / h (gear) |
| Indexed performance : | 590 kW |
| Continuous tensile force: | 143 kN |
| Driving wheel diameter: | 855 mm |
| Gear system : | Abbot , two-lamellar |
| Number of drive gears: | 2 |
| Size gears: | 840 mm (22 teeth) |
| Control type : | Heusinger-Walschaerts; Piston valve with internal inflow (adhesion) Heusinger-Walschaerts; Piston valve with external inflow (gear) |
| Number of cylinders: | 2 adhesion (high pressure), 2 gear (low pressure) |
| Cylinder diameter: | 455 mm |
| Piston stroke: | 450 mm |
| Cylinder d. Gear drive: | 455 mm |
| Piston stroke gear drive: | 430 mm |
| Boiler overpressure: | 14 bar |
| Number of smoke tubes: | 18th |
| Heating pipe length: | 3200 mm |
| Grate area: | 1.65 m² |
| Radiant heating surface: | 6.7 m² |
| Tubular heating surface: | 63.4 m² |
| Superheater area : | 20.9 m² (Schmidt system) |
| Water supply: | 4.0 m³ |
| Fuel supply: | 1800 kg (coal) |
| Brake: | Band brake (gear), Riggenbach counter pressure brake , vacuum block brake |
| Coupling type: | Center buffer; Subjacent screw coupling (delivery) or compensating coupling according to RhB standards (DFB) |
From 1923, nine of the steam locomotives of the type HG 4/4 were procured by the French colonial administration for use on the rack railway from Song Pha to Đà Lạt in French Indochina (now Vietnam). The rack-and - pinion locomotives built by the Swiss Lokomotiv- und Maschinenfabrik Winterthur (SLM) were immediately shipped to France and on to Asia, where they remained until the line was abandoned due to the war in the 1970s. Two machines, which were returned to Switzerland in 1990, have been preserved on the Furka Mountain Line Steam Railway (DFB), one of which is still being refurbished.
construction
At the time of the construction of the locomotives, SLM was able to fall back on extensive experience in the construction of rack-and-pinion locomotives. The basis for the HG 4/4 was the HG 4/5 cogwheel locomotive with the Winterthur drive system , which was delivered in 1914 in six and in 1920 in another four copies to the Nilgiri Railway in India . The performance could be increased again significantly, and the construction without running axles made it possible to use the total mass of the vehicle as a friction weight. The maximum passable gradient was planned to be 120 ‰, the trailer load should be a maximum of 65 tons on the adhesion and gearwheel sections. The SLM had already built the HG 2/3 and HG 3/4 (Abt system) locomotives earlier .
The locomotives have four coupling axles mounted in an inner frame . The frame is made of sheet metal and riveted. The adhesion drive takes place on the third coupling axis. The first and fourth axes can be moved sideways to improve cornering. The suspension is provided by leaf spring packages.
The boiler has a volume of 2.85 m³ and has 104 boiling and 18 smoke tubes. The total heating area is 92 m². The water supply is carried in lateral water tanks on both sides of the boiler. The boiler is fed by two non-sucking Friedmann injectors.
The total of four cylinders work in cogwheel operation in combination, with the adhesion cylinders below being designed as high-pressure cylinders and the cylinders of the gear drive installed above as low-pressure cylinders (" Winterthur system "). Thanks to this design, all important components are easily accessible on the outside of the locomotive, and there are no inclined cylinders required as in the "System Abt". (Both systems have in common that they do not need cranked axles as in a construction with inner cylinders, but consist of comparatively simple parts.) The gear drive consists of two coupled intermediate shafts that are installed above the drive gear shafts and these have a reduction of 1: 2 drive. The entire gear drive is mounted in the frame and is therefore part of the sprung mass; it can be adjusted in height to compensate for the wear on the bandages. Due to this construction with a gear, high and low pressure cylinders can have the same diameter despite the significantly different volume flow. The additional reduction also causes the gear drive to run in rack and pinion mode at twice the speed and in the opposite direction as the adhesion drive. The cylinders on the high pressure side, together with their valve body, each form a casting, while the two cylinders and valve bodies on the low pressure side are combined to form a casting. The entire cylinder block consists of three parts that are screwed to the locally reinforced frame. All cylinders are equipped with piston valves. The engines have a common Heusinger-Walschaerts control . In pure adhesion mode, the locomotive is only driven with the high-pressure cylinders (and then single-stage steam expansion). Conversely, when starting on a rack and pinion section, part of the boiler pressure can be applied to the gear drive via an auxiliary regulator.
The machines were delivered with central buffers and underlying screw couplings according to French standards. For operation in Switzerland, the screw couplings were replaced by couplings in accordance with the RhB standard.
The locomotive has a total of five brakes which, apart from the brake pads, are in their original condition from the 1920s. The two band brakes of the gear drive operated with hand spindles act on the intermediate shafts. The block brake acts on one side from the front on the first, third and fourth coupled wheel sets. The counter-pressure brake is usually used on downhill slopes ; there is also a suction air brake for the entire train, the brake cylinder of which acts on the adhesion brake linkage of the locomotive, and another manual spindle brake using the same brake linkage.
Auxiliary facilities are several grease guns for cylinders and the gear drive as well as an original steam generator for the electrical systems. As is customary in this environment, safety equipment was not retrofitted; operational safety is guaranteed by operating with two people.
history
Use in Indochina
The first five locomotives (No. 701-705, factory No. 2937-2941) were delivered in 1924 via France to the then Compagnie Génerale de Colonies Paris in Indochina. In 1929, the Esslingen machine factory built two more locomotives (No. 706/707, Factory No. 4227/4228) according to the plans of the SLM and also delivered them to France as part of reparation claims. The last two locomotives (No. 708/709 Factory No. 3413/3414) were again supplied by SLM. In Indochina, the machines were in use on the Song Pha (formerly Krong Pha) - Đà Lạt route.
Four machines were lost or destroyed during the Second Sino-Japanese War. In 1947 the locomotives still in existence were given the new numbers VHX 40 302, 303, 304, 306 and 308 from the South Vietnamese State Railways. The missing locomotives were replaced by the HG 3/4, which had been procured in 1947 and had been retired from the Furka-Oberalp-Bahn .
The Vietnam War repeatedly led to the destruction of both vehicles and the railway systems. In the end, three HG 4/4s survived in a more or less operational condition, namely the locomotives 304, 306 and 308. The last trips took place in 1975. The two SLM locomotives 304 and 308 were parked in the Đà Lạt depot. The Esslingen locomotive 306 was parked in the area of the Tháp Chàm railway workshop, occasionally used as a hot water and steam generator and otherwise neglected. When this locomotive was examined in 1990 for a possible return transport, many parts of the engine and superstructure as well as almost all of the fittings were missing.
Repatriation and revision
As part of the reactivation of the Furka mountain route in 1990, in addition to four HG 3/4 and the two HG 4/4 No. 40 304, resp. 704 and 40 308, respectively. 708, returned to Switzerland by the DFB in an elaborate “Back to Switzerland” campaign. The remains of the locomotive 306 resp. 706 had to be left behind in Vietnam for various reasons. The frame with wheel sets, gear drive and cylinder blocks did not come to Switzerland until 1998 via the port of Haiphong.
Since 2006, the two locomotives 704 and 708 have been faithfully rebuilt by qualified specialists in the DFB workshop in Chur. It was found that, with the exception of the wheelsets, very few parts come from other locomotives. The boilers were not exchanged either, the numbering corresponded to the records found in the SLM archive in Winterthur. The locomotives had suffered badly in the last few years of operation. As a result of the Vietnam War, the maintenance work was carried out in Đà Lạt, although the infrastructure for larger work was not available there. Many parts were worn far beyond the limit mass. The locomotive frames were so badly worn due to inadequate maintenance that, contrary to the original intention, they could no longer be refurbished with reasonable effort. They had to be rebuilt using parts that were still usable, which was achieved with generous support from external companies. At the end of 2011, the two frames were transferred from the assembly area in Winterthur to the Chur workshop.
Thus, the "foundation" was now in place to start building the locomotives. Work was only carried out in parallel where it was expedient, but otherwise the 704 locomotive was preferred. First, the cylinder blocks (steam engine) and the new pulling and pushing devices (MGB / RhB standard) required for operation on the Furka mountain route were installed so that the riveting work on the frame could be completed. Although the 706 locomotive was available as a spare parts donor, the left high-pressure cylinder as well as the cylinder and valve box covers had to be re-cast for the 704 locomotive. The necessary new construction plans were created using the original drawings by volunteer DFB employees using CAD.
At the same time, the extensive repair and revision work on the boiler of the 704 locomotive began. Due to the better experience with the old riveted boilers compared with replicated welded constructions in the factory on the Furka, it was decided to keep the old boilers. Several parts of the standing boiler had to be replaced, and a new copper fire rifle was manufactured in the workshop in Uzwil , which was moved into in 2013 . The smoke chamber including the smoke chamber pipe wall also had to be rebuilt. Furthermore, new steam collecting boxes and counter-pressure brake housings had to be cast. The newly created copper fire rifle was built into the revised boiler. The boiler forging work was also carried out by DFB staff in their own workshop. The fittings have been revised or newly made.
The Furka mountain route has smaller arc radii than the route in Vietnam. In order for the locomotives to be able to use the somewhat narrower bends at the DFB without any problems, a few minor adjustments were necessary on both the vehicle and the track side. On the locomotive side, it was investigated to increase the side play of the first and fourth coupling axles, but this could not be implemented. On the superstructure side, adjustments were necessary to the switch connections in Realp and Gletsch. The control arms of some other points have also been slightly corrected. (The DFB line has no rack and pinion turnouts.) This work was carried out in parallel to work on the locomotives as part of the ongoing construction and maintenance program.
During the reconditioning, many parts were manufactured or assembled using old methods, even if more modern methods were available. In particular, the frames are authentically riveted and not welded. It turned out that it is becoming increasingly difficult to find companies or people who can still carry out such work or who have the appropriate facilities.
In the early summer of 2018, locomotive 704 was completed and in a "rollout" on 16./17. June 2018 in Uzwil to the public. At this point about 48,000 man-hours had been worked on the two locomotives.
Use on the Furka mountain route
In contrast to all other DFB locomotives, the HG 4/4 were never in service in Switzerland. For the operation of these locomotives on the DFB network, an initial registration is required, which, in addition to the usual boiler certificates, resulted in the creation of extensive calculations and safety certificates, for example for safety against derailment and the behavior of the various braking systems. The first operating license was a provisional and permitted test drives, but not yet the transport of passenger trains.
The locomotive 704 was exhibited for a weekend in the Verkehrshaus and then brought to Realp. In the fully equipped workshop there, the last parts and fittings were assembled, some of which had been left out for the transport. In addition to the verification of the correct wheel loads, the control system was measured and precisely adjusted. The locomotive was heated up for the first time in mid-July 2018. After the last leaks had been eliminated, the first test drives could be made and soon the cogwheel route could also be driven with a load. The trips were gradually extended to the entire mountain route and continued until October 2018. After the end of these runs, the locomotive was subjected to a thorough inspection and, in particular, all relevant parts of the engine were examined for excessive wear. The open-ended operating license was issued shortly before Christmas. The first journeys with passenger trains took place at the end of June 2019.
literature
- Hans Hofmann: Brig Furka Disentis Bahn, steam locomotives . Calanda Verlag, Chur 1993. ISBN 3-905260-18-2
- Wolfgang Finke, Hans Schweers: The vehicles of the Furka-Oberalp-Bahn 1913-1999 . Brig-Furka-Disentis. Schöllenenbahn. Furka-Oberalp Railway. Schweers + Wall, Aachen 1999, ISBN 978-3-89494-111-6 .
- Johannes von Arx: Furka mountain route steam train . Furka adventure. Published by the Furka Mountain Route Steam Railway, Oberwald 2000
- Walter Frech, Michael Nold: The HG 4/4 704, an attractive addition to the locomotive on the Furka mountain route . Swiss Railway Review 6/2019, pp. 332–335.
