LNER Class P2

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LNER Class P2
LNER P2 Cock O' The North in 1934
2001, Cock O' The North
Type and origin
Power type Steam
Designer Sir Nigel Gresley
Builder Doncaster Works
Build date 1934-1936
Total produced 6
Specifications
Configuration 2-8-2
Leading wheel
diameter
3 ft 2 in (0.97 m)
Driver diameter 6 ft 2 in (1.88 m)
Trailing wheel
diameter
3 ft 8 in (1.12 m)
Wheelbase 37 ft 11 in (11.56 m) engine
16 ft 0 in (4.88 m) tender
64 ft 0.875 in (19.52943 m) total
Axle load 20 long tons (20 t) locomotive approx.
Locomotive weight 110 long tons 5 cwt (247,000 lb or 112 t) max.
Tender weight 55 long tons 6 cwt (123,900 lb or 56.2 t) max.
Boiler 6 ft 5 in (1.96 m) max. diameter
Boiler pressure 220 psi (1.5 MPa)
Firegrate area 50 sq ft (4.6 m2)
Heating surface:
– Tubes
1,354.2 sq ft (125.81 m2)
– Flues 1,122.8 sq ft (104.31 m2)
– Firebox 237 sq ft (22.0 m2)
– Total 3,349.5 sq ft (311.18 m2)
Superheater area 635.5 sq ft (59.04 m2)
Cylinders 3
Cylinder size 21 in × 26 in (530 mm × 660 mm)
Valve gear No. 2001 as built: Lentz rotary cam
No. 2001 from April 1938 and nos. 2002–6: Walschaerts outside, Gresley conjugated inside[1][2]
Valve type No. 2001 as built: Poppet, 8 inch (inlet) and 9 inch (exhaust)
No. 2001 from April 1938 and nos. 2002–6: piston valves, 9 inch[1]
Performance figures
Tractive effort 43,462 lbf (193.33 kN) at 85% boiler pressure
Career
Operator(s) London & North Eastern Railway
Retired 1943-1944
Disposition All rebuilt as LNER Thompson Class A2/2
Technical parameters: The Engineer. 1 June 1934 p.551 (refer to original design of No.2001)

The London and North Eastern Railway Class P2 was a class of 2-8-2 steam locomotives designed by Sir Nigel Gresley for working heavy express trains over the harsh Edinburgh to Aberdeen Line. As they were to serve on Scottish expresses, they were given famous names from Scottish lore.

Six locomotives of the class were built; introduced between 1934 and 1936. Between 1943 and 1944 the class were rebuilt under Gresley's successor Edward Thompson into the LNER Thompson Class A2/2 4-6-2 type.

History[edit]

Design[edit]

The locomotives were designed by Nigel Gresley to haul express trains over the difficult London to Aberdeen rail route on the London and North Eastern Railway. In the design Gresley was influenced by recent French practice, in particular passenger locomotives of the Paris à Orléans railway.[3]

The first locomotive of the class, No.2001 Cock o' the North, was introduced in 1934 - built at Doncaster Works,[4] with Hugo Lentz type,[citation needed] rotary-cam actuated poppet valve-gear supplied by the Associated Locomotive Equipment Company,[5] and a double chimneyed exhaust, each using four nozzle blastpipes (see KylChap).[6] The chimney system was designed to take different fittings to allow experimentation with exhaust arrangements.[citation needed]

The boiler barrel was of the design used on Gresley pacifics, fitted to a larger firebox, the front end design was of the same form as the Class W1, No. 10000 Hush-Hush locomotive, derived from Dr. Dalby's wind tunnel research, whilst the attached tender was a standard design as used of Gresley pacifics.[7] The design also introduced a wedge shaped cab front end, designed to give a better view out of the cab - the same design was used on the later A4 and V2 express engines.[8] No. 2001 was fitted with a Crosby chime whistle which Gresley had obtained from Cpt. Howey of the Romney, Hythe and Dymchurch Railway, and were originally intended for that railways Canadian Pacific style locomotives.[9][10]

The second locomotive of the class, No.2002 Earl Marischal was completed by 1935, also a Doncaster, and was fitted with a Walschaerts valve gear as used on Gresley pacifics, and had a greater superheater heating area of 776.5 sq ft (72.14 m2), obtained by using wider diameter fire tubes.[11] A low cutoffs smoke clearance on No.2002 was unsatisfactory - wind tunnel experiments led to an additional second pair of smoke deflectors being fitted inward of the first.[12]

No. 2002 proved to be the more efficient engine of the two, in part due to a lower cylinder clearance volume, as well as due to the stepped-cam cutoff modifications made to No.2001 reducing economical working relative to the infinitely variable cutoff of No.2002. As a result the following locomotives were built with piston based valve gear.[13]

By June 1936 the third engine had been produced; No.2003, Lord President, based on the design of No.2002 but with the external design modified by the use of streamlining as used on the Silver Link locomotives. (see LNER Class A4).[14] The locomotive weight was reduced to 107 long tons 3 cwt (240,000 lb or 108.9 t).[15] The wedge-shaped front was found to lift the engine's smoke clear of the driver's view;[15] No. 2002 was altered to this form in 1936, and No. 2001 in 1938.[16]

Three further locomotives Mons Meg, Wolf of Badenoch and Thane of Fife were also under construction at Doncaster in 1936.[14]

No. 2004 was fitted with an experimental butterfly valve blastpipe bypass, manually activated to prevent fire-lifting at high cutoffs, this was later replaced with a plug valve and higher bypass pipe diameter - both designs had problems with sticking due to carbonised deposits.[17] No. 2005 lacked the Kylchap double chimney of the rest of the class,[18] whilst the sixth locomotive of the class had a different boiler design, with a longer combustion chamber, and firebox heating area and volume of 253 sq ft (23.5 m2) and 319 cu ft (9.0 m3) respectively with a Robinson superheater.[15] The production series was completed in 1936.[citation needed]

Testing, performance and service[edit]

Shortly after being put into service, on 19 June No.2001 was tested with a 19 bogie carriage train of 649 tons on a return journey between Kings Cross, Grantham and Barkston; the locomotive hauled the train at an average speed of over 50 mph, with a peak speeds of over 70 mph.[19] Drawbar pulls of around 6 tons at around 60 mph were recorded - representing a peak power output of over 2000 horsepower.[20] In late 1934 the locomotive was sent to Vitry, France for static testing.[21]

Point contact on the infinitely variable cams of No.2001 led to cam damage after ~10,000 miles of service, resulting in the replacement with stepped cams giving six steps of cutoff (12, 18, 25, 35, 45 and 75%).[13] By 1939 No.2001 had had its rotary-cam poppet-valve valvegear replaced with Walschaerts gear.[22]

In 1939 E.H. Livesay reported from the footplate on the performance of No.2004 Mons Meg on the early morning 'Aberdonian' non-stop from Edinburgh to Dundee; a train with gross weight of 320 tons. Peak speeds of over 60 mph were noted, with 55 mph on a 1 in 100 gradient, and an average speed of 44.25 mph (71.21 km/h). Despite the vehicle's long wheelbase, 19 ft 6 in (5.94 m), and the frequent curves on the route, Livesay did not report any serious issues with ride quality.[23] On the return trip with a load of 360 tons gross, recording a peak of 68 mph on a 1 in 100 down section, with an average speed of 38 mph including several stops and speed restrictions. Livesay reported favourably on the acceleration of the train, recording 50 mph reached from standstill over 1.25 miles, with 60 mph reached in under 2 miles.[24] Further Edinburgh to Dundee and Return runs were made in the afternoon with 355 and 450 ton gross loads respectively with average speeds of 40.25 and 33 mph.[25]

Rebuilding[edit]

The class was rebuilt into Class A2/2 4-6-2 'Pacifics' during 1943/4.[26] Several contemporary observed that the rebuilding was due to the classes' wheelbase being too long for the routes it worked, and suggested that the railway would have been better served had the class been transferred to more suitable routes,[27] according to B. Spencer the class was rebuilt due to reliability issues during the difficult conditions of World War 2 period, and additionally to take the opportunity to try out a different valve gear arrangement.[28]

Railway author O. S. Nock suggested that Gresley's successor, Edward Thompson, may have made largely unsubstantiated criticisms of the class in order to justify the rebuilding.[26] According to O. Bulleid the class were not an inefficient design, but had been placed into services in which they were underutilised, leading to poor fuel economy.[29]

Locomotives[edit]

New build P2 proposals[edit]

The P2 Steam Locomotive Company[edit]

In 2010, the A1 Steam Locomotive Trust, who were responsible for the construction of 60163 Tornado, announced plans to hold a feasibility study into building a new P2 class locomotive, which would be numbered as 2007.[30]

The feasibility study was officially launched in October 2011 and was be broken into 3 stages.[citation needed]} The first stage involved creating an electronic model of a steam engine for track dynamic analysis; Tornado was used as the basis for this modelling, together with track position data supplied by Network Rail - Tornado was fitted with accelerometers during its testing- the data from which provided a basis to validate the modelling data and assumptions against.[31] The second and third stages are to involve creating a computer model of a P2, and then analysing modifications to the design using the computer software. Modelling data for the P2 design and a modified design with a LNER Class V2 type pony truck was published in early 2013. The rail-dynamics software used was Delta Rail's 'VAMPIRE' product.[31] The computer modelling showed acceptable dynamics and the project to build No. 2007 was officially launched in September 2013 at the A1 Convention with a seven to ten year construction timetable.[31]

The locomotive is said to share 70% commonality on parts with Tornado including the boiler and tender.[32] Modern modifications to the original design include roller bearings (also featured on Tornado) and an all-welded, all-steel boiler; the final build may utilise Caprotti valve gear rather than the Lentz or Walchaerts types fitted to the originals.[31] In most other respects and appearance the built 'No.2007' will match that of No.2001 Cock o' the North.[31]

On November 14, 2013 the P2 Steam Locomotive Company (P2SLC) announced that the name of its new P2 would be ‘Prince of Wales’, in honour of HRH Prince Charles, The Prince of Wales' 65th birthday.[33] Construction began in May 2014 with the locomotives's frames being cut at Tata Steel's Scunthorpe works.[34]

The project cost is estimated at £5,000,000.[33]

Doncaster P2 Locomotive Trust[edit]

The Doncaster P2 Locomotive Trust (Registered Charity Number 1149835), plans to build a replica P2 of the design as modified in 1938; using Gresley motion, Walschaerts valve gear, and a LNER A4 style 'Bugatti' streamlined front.[35] The locomotive's frames were cut in April 2014 at Tata Steel's, Wednesfield works.[36]

Modelling[edit]

In 2013 Hornby Railways collaborated with the A1 locomotive trust to produce models of the class, starting with the original P2 2001 Cock O' The North, for expected release in early 2014 in both a low level "Hornby Railroad" specification, and a more detailed version.[37][38]

References[edit]

  1. ^ a b Boddy et al. 1983, pp. 170, 171, 179, 182
  2. ^ Nock, O. S. (1966). The British Steam Railway Locomotive 1925-1965 II. Ian Allan. pp. 102–103. 
  3. ^ The Engineer. 1 June 1934 p.551, cols.1-2
  4. ^ The Engineer. 1 June 1934 p.551 col.1
  5. ^ The Engineer. 1 June 1934 p.551 cols.2-3
  6. ^ The Engineer. 1 June 1934 p.552 col.1-2
  7. ^ The Engineer. 1 June 1934 p.552 col.3
  8. ^ Spencer 1947, pp. 190-191.
  9. ^ Spencer 1947, p. 191.
  10. ^ No. 9 Winston Churchill, Romney Hyth and Dymchurch Railway, retrieved Dec 2013, .. a pair of Crosby chime whistles that Howey had bought in Canada, and had impressed Nigel Gresley on a visit to the RH&DR. Howey then presented Gresley with the second whistle which in turn was fitted to the new LNER express Cock o' the North 
  11. ^ "Locomotives and Railcars of 1934", The Engineer 159, 4 Jan 1935: 16 
  12. ^ Spencer 1947, p.193; Fig.33, p.192.
  13. ^ a b Spencer 1947, p. 193.
  14. ^ a b "Raid and Road", The Engineer 161, 26 June 1936: 677 
  15. ^ a b c "L.N.E.R. - New Locomotives", The Engineer 162, 3 July 1936: 20 
  16. ^ Boddy et al. 1983, p. 169
  17. ^ Spencer 1947, pp. 193-194.
  18. ^ Livesay 1939, p.342 col.2.
  19. ^ "Cock o' the North", The Engineer 157, 29 June 1934: 645 
  20. ^ "Dynamometer Tests of "Cock o' the North"", The Engineer 158, 6 July 1934: 16–17 
  21. ^ "Railway and Road Matters", The Engineer 158, 14 Dec 1934: 593 
  22. ^ Livesay 1939, p.342 col.3.
  23. ^ Livesay 1939, p.342 col.3; p.343 col.1.
  24. ^ Livesay 1939, p.343 cols.1-2.
  25. ^ Livesay 1939, p.343 col.3; 344 col.1,2.
  26. ^ a b Nock, O.S (1984), British Locomotives of the 20th Century 2, Book Club Associates, London 
  27. ^ Spencer 1947, Discussion p.220 (O.S.M. Raw); p.230 (Sutherland).
  28. ^ Spencer 1947, p. 234.
  29. ^ Spencer 1947, Discussion of paper p.211-212.
  30. ^ Gresley P2 study announced, A1 Steam Locomotive Trust, 25 April 2010 
  31. ^ a b c d e Design, The P2 Steam Locomotive Company, retrieved Nov 2013 
  32. ^ Mission / Introduction, The P2 Steam Locomotive Company, [it] has around 70% commonality with Tornado, including the boiler, tender and many other detailed fittings 
  33. ^ a b Walter, Andy (14 November 2013), Steam engine will be named after the Prince of Wales, The Northern Echo 
  34. ^ "Prince of Wales P2 steam locomotive construction starts", BBC News Humberside, 21 May 2014 
  35. ^ Mission Statement, Doncaster P2 Locomotive Trust, retrieved Nov 2013 
  36. ^ Fisher, Andy; Fisher, Dandan, eds. (April 2014), Cutting the frames for LNER P2 "COCK O' THE NORTH" (video), youtube 
  37. ^ Hayes, James (27 September 2013), Hornby Gresley Class P2 Mikado 2-8-2, The P2 Steam Locomotive Company 
  38. ^ Walker, Andy (20 October 2013), "Darlington steam engine plans have a model future", www.darlingtonandstocktontimes.co.uk 

Sources[edit]

Literature[edit]

  • "2‐8‐2 Type express passenger locomotive, London & North Eastern Railway". Journal of the Institution of Locomotive Engineers 24 (120): 469–426. 1934. doi:10.1243/JILE_PROC_1934_024_041_02.  edit

Rebuilds[edit]

  • Frost, Malcolm S. (10 April 2014), Fisher, Andy; Fisher, Dandan, eds., LNER P2 Class (lecture , video), youtube 

External links[edit]