LNER class P2

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LNER Class P2
LNER 2001 "Cock o 'the North" (1934)
LNER 2001 " Cock o 'the North " (1934)
Numbering: LNER 2001-2006
Number: 6th
Manufacturer: LNER Doncaster Works
Year of construction (s): 1934-1936
Retirement: 1943–1944 (conversion to LNER class A2, wheel arrangement 2'C1 ')
Axis formula : 1'D1 'h3
Gauge : 1435 mm ( standard gauge )
Length over buffers: 22,692 mm
Fixed wheelbase: 5,943 mm
Total wheelbase: 11,557 mm
Service mass: 112.0 t
Service mass with tender: 168.0 t
Friction mass: 82.0 t
Top speed: 125 km / h
Driving wheel diameter: 1,880 mm
Impeller diameter front: 965 mm
Rear wheel diameter: 1,118 mm
Control type : Lentz, Walschaerts
Number of cylinders: 3
Cylinder diameter: 533 mm
Piston stroke: 660 mm
Boiler overpressure: 15.3 bar
Grate area: 4.65 m²
Superheater area : 59.0 m²
Evaporation heating surface: 251.0 m²
Tender: 4-axis
Water supply: 22.7 m³
Fuel supply: 8.2 t
Control: Lentz / Walschaerts

The LNER class P2 steam locomotives of the British railway company London and North Eastern Railway (LNER) were procured between 1934 and 1936. The tender locomotives with the wheel arrangement 1'D1 ' ("Mikado") based on a design by LNER chief engineer Sir Nigel Gresley were specially designed for express train service on the route from Edinburgh to Aberdeen and the most powerful express steam locomotives ever built for a British railway company. Due to high coal consumption and consumer issues she let Gresleys successor Edward Thompson from 1943 in Pacific's the LNER Class A2 rebuild.

history

The increasing train weights of the express trains on the steep and winding main line of the LNER in Scotland from Edinburgh via Dundee to Aberdeen meant that the existing Pacific locomotives of the A1 and A3 classes were increasingly inadequate. A Pacific could carry a maximum load of 480 tons in the direction of Aberdeen and 420 tons in the direction of Edinburgh on the route. Increasingly, pre-tensioning vehicles had to be used to move trains weighing over 500 tons.

Nigel Gresley, LNER's chief engineer, therefore began to work on developing a more powerful express train locomotive to enable express trains weighing up to 600 tons on the route to Aberdeen without a leader locomotive. The good experiences that had been made in France at the Chemin de fer de Paris à Orléans (PO) with the conversions by André Chapelon on the basis of thermodynamic findings also attracted the attention of the British railway engineers. When designing the P2, Gresley therefore paid particular attention to favorable internal flow conditions in the steam circuit. He also adopted the Kylchap double chimney developed by Chapelon and the particularly high superheater temperatures typical of Chapelon designs . With the LNER class K3 , the LNER had good experience with slightly higher speeds with a Bissel frame , on this basis Gresley saw it as justifiable to dispense with the conventional two-axle bogie otherwise used for express train locomotives in favor of a single leading axle . The new express locomotive was therefore designed as a Mikado locomotive with the 1'D1 'wheel arrangement, which is otherwise rarely used by British railways for locomotives with a tender, in order to achieve sufficient traction. Previously, only the two locomotives of the LNER class P1 were equipped with this wheel arrangement at LNER , but they were freight locomotives .

The first locomotive with the number 2001 was completed in May 1934 in the LNER workshops in Doncaster , the second engine with the number 2002 followed in October of the same year. The 2001 was a Lentz - valve control , the second a conventional Walschaerts control with the typical Gresleys locomotives mechanical actuation of the inner cylinder on the controls of the outer cylinder. The two mighty locomotives were by far the largest express train locomotives in Great Britain. On test drives, the P2 showed the expected performance. In June 1934 the 2001 carried a test train of 660 tons on an incline of 5 ‰ at a speed of over 80 km / h. The maximum output was determined to be 2100 hp , making the P2 the most powerful British express steam locomotive. Due to the good results, another four pieces were ordered in Doncaster in mid-1934.

In December 1934, the P2 2001, accompanied by Gresley's personal assistant Oliver Bulleid, came to the French Vitry-sur-Seine for two months for test purposes at the stationary measuring stand there. However, the locomotive initially did not perform as expected on the measuring stand, since the axle bearings were already overheating before the maximum possible performance was reached, due to the lack of cooling due to the lack of airflow on the stationary system. Chapelon therefore suggested normal test drives, which the locomotive then completed between Tours and Les Aubrais . In terms of coal consumption and power development, however, the P2 did not come close to Chapelon's conversion 2'D locomotives. With the results obtained in France, the induced draft system was further optimized. The other P2s already ordered received the Gresley-Walschaerts control of the P2 2002 based on the tests with the first two locomotives. The Lentz valve control of the P2 2001 had not proven itself and led to high coal consumption, so it was replaced some time later. The ACFI feed water preheater used had also not proven itself . It was removed from the P2 2001, the remaining P2 did not have a preheater.

From the summer of 1935, the P2 took over their first scheduled services between Edinburgh and Aberdeen, for which a locomotive was stationed in Edinburgh Haymarket and Dundee. Both drove two pairs of trains a day between Edinburgh and Dundee and Dundee and Aberdeen, respectively. In 1936 the four more P2s that had been ordered came into service and added to the first two copies. Analogous to the streamlined locomotives of the LNER class A4 delivered from 1935 , the P2 delivered in 1936 received streamlined cladding. The other two P2 were also equipped with the streamlined fronts on the occasion of their first major workshop visits until 1937.

All six copies of the P2 were given names related to Scottish history . The 2001 was named " Cock o 'the North ", by which the entire class was known, after the nickname of the Chiefs of Clan Gordon . The other locomotives with the numbers 2002 to 2006 were given the names " Earl Marischal ", " Lord President " (after the Lord President of the Court of Session , the chairman of the Scottish Supreme Courts), " Mons Meg ", " Thane " of Fife ”(based on a character from Shakespeare's drama Macbeth ) and“ Wolf of Badenoch ”.

The former P2 2005 " Thane of Fife " as a converted A2 / 2-Pacific, with BR number 60505 in 1958

In the years after 1936, on the winding route to Aberdeen, there were repeated damage and high maintenance costs on the first coupled axle and problems with the leading frame, similar to the LNER class V2 , which was equipped with the same frames later in the war years was. The large grate also required considerable physical effort from the heater at full power, even if an extremely high coal consumption only occurred in the " Cock o 'the North " with its Lentz valve control. The locomotives therefore acquired a rather mixed reputation among the LNER staff and the responsible engineers, regardless of their high performance. Edward Thompson , Gresley's successor after his death in 1941, did not consider the locomotives to be suitable for long-term use with the LNER due to their small number. In 1943 and 1944 he had it converted in Pacifics type A2 / 2 according to his own design and thus ended the short history of the only British express locomotive with four coupled axles for the time being. Many experts criticized this decision, especially since the converted machines performed worse than the other LNER-Pacifics.

technical features

Despite various innovations, Nigel Gresley used many components from earlier designs for the P2. In addition to the lead frame derived from the K3, this also affected the boiler with a combustion chamber , which was a modified version of the A3 boiler, but with a larger fire box and grate surface . The P2 2006 “ Wolf of Badenoch ” received a slightly longer combustion chamber and a shorter smoke chamber to compensate for the same length of pipe. Instead of a conventional steam dome, there was a flat steam collector in the boiler. The frame was designed in a combined sheet metal and cast steel design. The driver's cab of the P2 was wedge-shaped, similar to a wind cutter. The first two locomotives were not given full cladding, but rather smoke deflectors . For better aerodynamics and the evacuation of the escaping steam from the driver's cab, the top of the smoke chamber was sloped, which gave the locomotive an impressive look from the front.

Like almost all of Gresley's designs, the locomotives were given a three-cylinder drive with - apart from the one initially equipped with Lentz valve control with a rotating control shaft in 2001 - the control design he developed , in which the slide of the inner cylinder was articulated mechanically via the control of the slide of the outer cylinder. The driving axle was the second coupled axle for all three cylinders . All three cylinder blocks were cast in one piece as a so-called monobloc , based on Gresley's previous good experience with this design, together with the valve boxes and the support for the smoke chamber , which reduced the weight and should reduce possible problems with leaks in the steam lines. The P2 block weighed almost seven tons due to its size. With the exception of the P2 2005 “Thane of Fife”, like the first two copies, all the P2 series got the Kylchap double chimney, which was designed for optimal suction with the lowest possible counter pressure. The 2005 got a single chimney for testing.

According to the small technical differences, the six locomotives were divided into three sub-classes. The 2001 “ Cock o 'the North ” with its valve control was classified as class P2 / 1 and the 2006 “ Wolf of Badenoch ” as class P2 / 3 due to the differently dimensioned boiler, the other four locomotives as class P2 / 2.

Replica of P2 locomotives

All P2 were converted into A2 / 2 Pacifics. These were taken over by British Railways with the nationalization in 1948 and retired in the course of the conversion to diesel locomotives by 1961. None of the original P2 or the converted A2 / 2 remained.

After the successful replica of a LNER-Class A1 Peppercorn Pacific , which has been in service as the 60163 " Tornado " since 2008 , the A1 Steam Locomotive Trust decided on a P2 replica as the next project. The P2 Steam Locomotive Company (P2SLC) was founded as a subsidiary for this purpose . The cost is estimated at around £ 5 million . Around 70% of the components of the P2 are identical to the A1, so that the experience gained there can be used. The P2 should largely correspond to the original status of the series in 1934, i.e. without the streamlined cladding that was later added and comparable to the A4. However, some of the weaknesses of the original design are to be eliminated, for example the new P2 receives a modified lead frame similar to the LNER class V2 . Adaptations to today's safety requirements and the equipment with compressed air brakes instead of the vacuum brake still used in Great Britain in the 1930s are further changes.

In May 2014, frame construction began at Tata Steel Works in Scunthorpe . The construction time is estimated at around seven years, at the start of construction donations of around 750,000 pounds had been received. In March 2015, a third of the required funds had already been received. In honor of Charles, Prince of Wales , the new P2 is to be named " Prince of Wales ". The Prince of Wales had financially supported the construction of the A1 “ Tornado ” and in 2009 formally gave the locomotive its name, which has been used several times in front of the Royal Train since it was commissioned .

Another replica was started by the Doncaster P2 Locomotive Trust in 2014. The aim of this replica is the replica with streamlined cladding, as all P2 had in the last few years before their conversion to the A2 / 2.

literature

  • OS Nock: The British Steam Railway Locomotive, Volume 2, 1925-1965 , Ian Allan Ltd., London 1966, pp. 102-105
  • Wolfgang Messerschmidt: 1D1. Success and fate of the Mikado locomotives. Franckh'sche Verlagshandlung, Stuttgart 1963, pp. 61–63

Web links

Commons : LNER Class P2  - collection of pictures, videos and audio files

Individual evidence

  1. ↑ a b H.CB Rogers: Express steam locomotive development in Great Britain and France. Haynes Publishing, Sparkford 1990, ISBN 0-86093-469-1 , p. 85
  2. ↑ P2SLC: Mission / Introduction , accessed on April 12, 2015
  3. ↑ Stuart Nathan: Raising steam. The Engineer, June 10, 2014 , accessed April 12, 2015
  4. ↑ BBC News: Prince of Wales P2 steam locomotive construction starts , May 21, 2014 , accessed April 12, 2015
  5. ^ The Northern Echo: Third of funds raised for multi-million pound steam engine project. March 21, 2015 , accessed April 12, 2015
  6. ↑ The Northern Echo: Steam engine will be named after the Prince of Wales , November 14, 2013 , accessed April 12, 2015
  7. ↑ Doncaster P2 Locomotive trust: Mission Statement ( Memento of the original dated December 3, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , accessed April 12, 2015 @1@ 2Template: Webachiv / IABot / www.cockothenorth.co.uk