Ing L.D.Porta Designed 3 Cylinder Compound 2-8-2t

I am indebted, again, to Shaun McMahon for providing these details of the L.D. Porta designed metre gauge LVM801 compound 2-8-2t type. Much of what follows comes from a document written by Shaun entitled: "STEAM LOCOMOTIVE 801 SERIES. A BRIEF TECHNICAL SUMMARY WITH RESPECT TO APPLICATION ON TREN A LAS NUBES." The document is dated 11th March 2000. Any mistakes contained below, however, are mine.

LVM stands for Locomotora Vapor Moderna - Modern Steam Locomotive.

The outline of LVM801 including numbered items and other details.

The outline of LVM801 including numbered items and other details.

LVM801 came out of a proposal to provide a modern steam locomotive for the Argentine 'Train to the Cloud' (Tren a Las Nubes) operation. In 2004 I travelled on Tren a Las Nubes. Click here to see the photos which give an impression of this amazing route.

The design incorporates all available modern steam locomotive technology. L.D. Porta incorporated his own extensive personal experience of working the Salta - Socompa line in to the design. From 1969, whilst working as Head of Thermodynamics Department for INTI, Porta was called upon by the State Railways of Argentina in order to solve the problems suffered with severe and widespread cases of priming that were being experienced. The result, now known as Porta Treatment (see here), was a system based upon the French TIA method but with a much coarser control suited to the lower technical level in Argentina. Oil burning metre gauge C16 class 4-8-2 No. 1802 was used for water treatment trials. These progressed to the stage where the boiler was washed out only twice in one full year. Boiler maintenance was said to be negligible despite the engine working in hard water districts known locally as 'boiler cemeteries'. At this stage Porta took the opportunity to modify locomotive No. 1802 (improved exhaust system, steam distribution due to improved valves and valve gear, improved combustion system etc.) which resulted in the maximum equivalent drawbar power reaching 1,300 kW (1743 hp), approximately 70% higher than for the original design, whilst the fuel productivity expressed in gross ton-km per kg of oil was also increased by 70%. This locomotive saw regular service on the Salta - Socompa section of the Northern Transandine Railway and could take the maximum load for the lines E4 and E5 class 2-10-2's at double the speed usually made by the standard locomotives up the steepest gradients.

It can be seen from the above what could be achieved with a modified locomotive, with this information specifically relating to the Salta line, it is not so difficult to predict the performance of a new steam locomotive specifically designed for the exacting conditions to be found at Tren a las Nubes.

In December 1999 Shaun McMahon had discussions with members of the Tren a las Nubes board of directors. These related to the performance and esthetic value of the locomotive, after all the main reason for reintroducing steam to the line would be to attract more passengers. Hence this design of locomotive gives the equivalent of a GM diesel in terms of operating flexibility, minimum maintenance cost, maximum availability, restricted axle loading, ease of operation whilst retaining the very elegant form of the traditional Stephenson steam locomotive.

It is very interesting, at this stage, to note the design drawn up some years ago by Porta, whilst working for INTI, for the metre gauge Belgrano Railway. The design was an entirely new 2-10-2. This was done at the request of the Industry Ministry, but never got beyond the design stage. The locomotive would have been a 3 cylinder compound with steam jacketed cylinders. The rated indicated power was to have been 3,730 kW (5002hp) and the maximum speed was 130 kph (81mph). The maximum axle load of 16.6 tons it would have been suitable for most of the Belgrano Railway system.

The LVM801 type is a 2-8-2 wheel arrangement, 3 cylinder compound, tank locomotive. Water and fuel supplies are carried on board the locomotive thus giving maximum 'ballast' adhesion rather than relying upon a tender which only adds to the dead weight of the train. However, a reserve water tank car is provided as part of the LVM801 design. An important part of the design philosophy being that the coupling between the tank car and the locomotive is of a standard train coupling type along with quick release couplings for the water supply; hence it can be detached just as easily as any other part of the train consist i.e. it is not a tender and in this form it forms part of the train and not the locomotive. The construction weight of the car is kept to a minimum with the major consideration being the weight of the water. Whilst working up hill water would be used from the water car so as keep the locomotives reserves intact in order to maximise adhesion. The final wheel arrangement of the tank car is under consideration. The proposed locomotive is an oil burner using the latest developments to date so as to maximise combustion efficiency, minimise fuel consumption and maximise environmental friendliness.

A cleaned up version of Porta's LVM801 outline.

A cleaned up version of Porta's LVM801 outline.

As mentioned above, the wheel arrangement is of 2-8-2 layout. Driving axle load is 16.5 T whilst carrying axle load is 10 T. Driving wheel diameter is 1 metre (3' 3") whilst carrying wheel diameter is 600 mm (1' 11½"). The wheels of the crankshaft axle are flangeless. The locomotive would be fitted with Southern type valve gear throughout. Sanders are fitted fore and aft and provision has been made to fit 2 air brake pumps to the locomotive. Compounding is an important feature of steam locomotive design and such has been used to its full extent in conjunction with the development of the LVM801 series. Porta advanced the compounding of steam locomotives to a great extent over the years. In brief the LVM801 has a 20 bar (290psi) high pressure cylinder fitted to the left hand side with 8 bar (116psi) low pressure cylinders fitted in the middle and right hand side of the locomotive. Indicated horsepower is rated at 2,200 HP (1641 kW). Full advantage has been taken in this design to provide for maximum (exaggerated) insulation of boiler and cylinders so as to reduce thermal losses (efficiency drop). The boiler itself has been designed to incorporate a Belpaire firebox with 'unvertical' sidewalls. Grate area is 4 square metres. The boiler has been placed as high as possible so as maximise firebox volume (combustion chamber) and allow for unrestricted primary air entry for combustion. Boiler support links replace the conventional expansion plates normally fitted to steam locomotive boilers. The boiler has been designed with a high degree of superheat so as to maximise efficiency. The exhaust system would be of the double Lempor type as this is the most advanced type of exhaust system to be designed and fitted to steam locomotives to date. However research and design work continues in this branch of steam locomotive engineering and the next type of exhaust system to be tested in service once final design work is complete will be the Lemprex exhaust system. Provision could be made to fit the latter once 'in service' testing has been completed on an existing locomotive. Full internal streamlining of the steam circuit has been incorporated into the design. Two feed water pumps are provided along with feedwater heaters. The fuel tank is in the region of 4 cubic metres (880 gallons) and thus provides sufficient fuel for a return trip of nearly 500 km (310 miles). The opportunity has been taken to provide easy smokebox access by designing the largest opening door possible.

Poor cab design, from which many locomotives suffer, having poorly laid out controls etc cause severe unpleasantness for crews. The cab of LVM801 has been designed so as to provide maximum ergonomic efficiency. Heating is also provided for cold weather working as due to the much improved boiler and outer firebox insulation. Extreme heat losses are not no longer suffered. These losses in the past (associated with poorly designed locomotives) have been used quite happily by crews to provide cab heating during cold conditions, by the same token the same thermal losses have been the cause of almost torturously hot conditions within locomotive cabs worldwide often resulting in severe heat exhaustion for drivers and firemen.

This locomotive has yet to be built but despite the time since the initial proposal it is not 'dead in the water'. In the recent economic climate it would have been a great achievement if LVM801 had been built. It is to be hoped one day in the not too distant future LVM801 will replace the diesels at Tren a las Nubes.

LVM801 Specifications & Statistics
Indicated Output
1641 kW
Boiler Pressure
25 Bar
Grate Area
43 feet²
Driving Wheel Diameter
1 metre

Carrying Wheel Diameter

Driven Wheels Axle Load
16.25 tons
16.5 tonnes
Carrying Wheels Axle Load
9.8 tons
10 tonnes
Maximum Weight in Service
182 tons
185 tonnes
Fuel Capacity (Gas Oil)
880 gallons
Range based on fuel capacity
310 miles
500 km

The 2003 version of LVM801. Courtesy of Shaun McMahon.

The 2003 version of LVM801. This excellent illustration was prepared by Hugh Odom. Courtesy of Shaun McMahon.

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