 | This article needs additional citations for verification .(December 2024) |
The Diesel-Zarlatti locomotive was a prototype railway locomotive, built in Italy in 1929, which adopted a hybrid diesel-steam transmission system.
| | This article needs additional citations for verification .(December 2024) |
The Diesel-Zarlatti locomotive was a prototype railway locomotive, built in Italy in 1929, which adopted a hybrid diesel-steam transmission system.
In the 1920s, there was a search for alternatives to the steam locomotive for railway traction, to reduce cost and improve efficiency. The main alternatives were railway electrification or the use of an internal combustion engine, such as the diesel engine.
A disadvantage of the internal combustion engine was the need for a transmission system. One option to be explored was the conversion of an existing steam locomotive by fitting a diesel engine and an air compressor to supply compressed air to the existing steam cylinders. This was the constructive principle on which the Zarlatti locomotive was based. It may be seen as a development of the earlier Mekarski system. [1]
Between 1928 and 1929 FS steam locomotive number 910.042 was modified at the Royal Arsenal of La Spezia to test the system, which was based on the patents of the inventors Fausto Zarlatti and Umberto Simoni. If the system had been a success, it could have led to the modification of a large number of FS steam locomotives and the avoidance of the need to build new locomotives.
The tests took place on the Rome–Lido railway from 6 April to 25 April 1929 with 16 round-trip pairs. The maximum speed reached with a tail load of 101 tonnes was 74 km/h. [2] The experiment had some success but there were problems: On 17 April, the piston of the engine water circulation pump broke and on 23 April a pipe attached to the Westinghouse brake compressor became detached. The experiment, for these reasons, was not pursued.
The boiler and superstructure were removed from the locomotive in the arsenal workshop at La Spezia but the original compound expansion steam cylinders were left in place. A six-cylinder, two-stroke, diesel engine built by Fiat-San Giorgio was installed. This engine produced 325 hp at 450 rpm and drove a rotary compressor, built by a Swiss company in Winterthur, which delivered compressed air at 8 bar pressure. A small naphtha-fired boiler with a heating surface of 52 square metres was also installed for the production of steam. Cooling water from the engine and compressor was fed into the boiler at about 70 °C. For cold starting, the boiler was used to preheat the diesel engine. When the locomotive started from rest, the original steam cylinders were fed with steam alone, but when running they were powered by a mixture of steam and compressed air. The steam was needed to prevent the cylinders icing up, because compressed air cools when it expands.
An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy.
A steam engine is a heat engine that performs mechanical work using steam as its working fluid. The steam engine uses the force produced by steam pressure to push a piston back and forth inside a cylinder. This pushing force can be transformed by a connecting rod and crank into rotational force for work. The term "steam engine" is most commonly applied to reciprocating engines as just described, although some authorities have also referred to the steam turbine and devices such as Hero's aeolipile as "steam engines". The essential feature of steam engines is that they are external combustion engines, where the working fluid is separated from the combustion products. The ideal thermodynamic cycle used to analyze this process is called the Rankine cycle. In general usage, the term steam engine can refer to either complete steam plants, such as railway steam locomotives and portable engines, or may refer to the piston or turbine machinery alone, as in the beam engine and stationary steam engine.
A steam locomotive is a locomotive that provides the force to move itself and other vehicles by means of the expansion of steam. It is fuelled by burning combustible material to heat water in the locomotive's boiler to the point where it becomes gaseous and its volume increases 1,700 times. Functionally, it is a steam engine on wheels.
A diesel locomotive is a type of railway locomotive in which the power source is a diesel engine. Several types of diesel locomotives have been developed, differing mainly in the means by which mechanical power is conveyed to the driving wheels. The most common are diesel–electric locomotives and diesel–hydraulic.
Engine braking occurs when the retarding forces within an internal combustion engine are used to slow down a motor vehicle, as opposed to using additional external braking mechanisms such as friction brakes or magnetic brakes.
The British Railways Class D3/7 is a class of 0-6-0 diesel electric shunting locomotives built as LMS Nos. 7080–7119. The class were built from May 1939 through to July 1942 by the London, Midland and Scottish Railway at their Derby Works using a diesel electric transmission supplied by English Electric.
A gas turbine locomotive is a type of railway locomotive in which the prime mover is a gas turbine. Several types of gas turbine locomotive have been developed, differing mainly in the means by which mechanical power is conveyed to the driving wheels (drivers). A gas turbine train typically consists of two power cars, and one or more intermediate passenger cars.
A fireless locomotive is a type of locomotive which uses reciprocating engines powered from a reservoir of compressed air or steam, which is filled at intervals from an external source. They offer advantages over conventional steam locomotives of lower cost per unit, cleanliness, and decreased risk from fire or boiler explosion; these are counterbalanced by the need for a source to refill the locomotive, and by the limited range afforded by the reservoir.
A retarder is a device used to augment or replace some of the functions of primary friction-based braking systems, usually on heavy vehicles. Retarders serve to slow vehicles, or maintain a steady speed while traveling down a hill, and help prevent the vehicle from unintentional or uncontrolled acceleration when travelling on a road surface with an uneven grade. They are not usually capable of bringing vehicles to a standstill, as their effectiveness diminishes as a vehicle's speed lowers. Instead, they are typically used as an additional aid to slow vehicles, with the final braking done by a conventional friction braking system. An additional benefit retarders are capable of providing is an increase in the service life of the friction brake, as it is subsequently used less frequently, particularly at higher speeds. Additionally, air actuated brakes serve a dual role in conserving air pressure.
A swing-piston engine is a type of internal combustion engine in which the pistons move in a circular motion inside a ring-shaped "cylinder", moving closer and further from each other to provide compression and expansion. Generally two sets of pistons are used, geared to move in a fixed relationship as they rotate around the cylinder. In some versions the pistons oscillate around a fixed center, as opposed to rotating around the entire engine. The design has also been referred to as a oscillating piston engine, vibratory engine when the pistons oscillate instead of rotate, or toroidal engine based on the shape of the "cylinder".
The LNER W1 No. 10000 was an experimental steam locomotive fitted with a high pressure water-tube boiler. Nigel Gresley was impressed by the results of using high-pressure steam in marine applications and so in 1924 he approached Harold Yarrow of shipyard and boilermakers Yarrow & Company of Glasgow to design a suitable boiler for a railway locomotive, based on Yarrow's design.
Engine efficiency of thermal engines is the relationship between the total energy contained in the fuel, and the amount of energy used to perform useful work. There are two classifications of thermal engines-
A steam diesel hybrid locomotive is a railway locomotive with a piston engine which could run on either steam from a boiler or diesel fuel. Examples were built in the United Kingdom, Soviet Union and Italy but the relatively high cost of fuel oil, or failure to resolve problems caused by technical complexity, meant that the designs were not pursued.
The Mekarski system was a compressed-air propulsion system for trams invented by Louis Mékarski or Louis Mékarsky in the 1870s. He worked in France, was born in 1843 in Clermont-Ferrand of Polish origin. Many references to him use the Polish name Ludwik Mękarski.
The counter-pressure brake, also named the Riggenbach counter-pressure brake after its inventor, Niklaus Riggenbach, is a dynamic railway brake on steam locomotives that brakes the locomotive using the driving cylinders. In doing so it reduces wear and tear and overheating of the driving wheel tyres and brake blocks and enables a continuously high brake force to be applied. The brake works by using the cylinders as air compressors and converting kinetic energy into heat. Steam is emitted during braking but this does not come from the boiler, it is produced by evaporation of water used to cool the cylinders.
The Still engine was a piston engine that simultaneously used both steam power from an external boiler, and internal combustion from gasoline or diesel, in the same unit. The waste heat from the cylinder and internal combustion exhaust was directed to the steam boiler, resulting in claimed fuel savings of up to 10%.
The Great Northern Railway (GNR) Class L1 was a 0-8-2T side tank steam locomotive designed by Henry Ivatt. It was originally designed for suburban passenger traffic on the Metropolitan City Lines.
An internal combustion engine is a heat engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine, the expansion of the high-temperature and high-pressure gases produced by combustion applies direct force to some component of the engine. The force is typically applied to pistons, turbine blades, a rotor, or a nozzle. This force moves the component over a distance. This process transforms chemical energy into kinetic energy which is used to propel, move or power whatever the engine is attached to.
FS Class 910 were 2-6-2 tank locomotives designed by Guglielmo Cappa for Rete Sicula where they were registered as RS Class 400. They were absorbed by Italian State Railways (FS) in 1905 and became FS Class 910.
A Naphthalene locomotive was tested in France in 1913. It was built by Schneider-Creusot for use in their own plant.