The London, Midland and Scottish Railway (LMS) Princess Royal Class is a class of express passenger steam locomotive designed by William Stanier. They were Pacifics (i.e. had a 4-6-2 wheel arrangement). Thirteen examples were built at Crewe Works, between 1933 and 1935, and two are preserved.
A prototype batch of three locomotives was to be constructed in 1933. Two were constructed as drawn but the third set of frames was retained as the basis for an experimental turbine locomotive. 
The third prototype was constructed with the aid of the Swedish Ljungstrom turbine company and known as the Turbomotive, although not named. It was numbered 6202, in sequence with the Princess Royals. Although 'generally similar' to the rest of the Princess Royals, and 'not all that much different', it used a larger 40 element superheater to give a higher steam temperature, more suitable for turbine use.[note 1] This boiler was also domeless as would later be used for the second batch of the Princess Royals. The continuous exhaust of the turbine, rather than the sharper intermittent blast of the piston engine, also required changes to the draughting and the use of a double chimney. It entered service in June 1935 on the London–Liverpool service.
A second batch of eleven locomotives was constructed later.
Each locomotive was named after a princess, the official name for the class was chosen because Mary, Princess Royal was the Commander-in-Chief of the Royal Scots. However, the locos were known to railwaymen as "Lizzies", after the second example of the class named for Princess Elizabeth who later became Queen Elizabeth II of the United Kingdom. Later examples of 4-6-2 express passenger locomotive built by the LMS were of the related but larger, Coronation Class.
The class was withdrawn in the early 1960s in line with British Railways' modernisation plan.
|6200||46200||The Princess Royal||27 July 1933||17 November 1962||Last to be withdrawn|
|6201||46201||Princess Elizabeth||3 November 1933||20 October 1962||Preserved.|
|6203||46203||Princess Margaret Rose||1 July 1935||20 October 1962||Preserved. Owned by the Princess Royal Class Locomotive Trust.|
|6204||46204||Princess Louise||19 July 1935||7 October 1961||.|
|6205||46205||Princess Victoria||24 July 1935||25 November 1961||Fitted with modified valve gear in 1947. Converted back to normal in 1955|
|6206||46206||Princess Marie Louise||1 August 1935||20 October 1962||.|
|6207||46207||Princess Arthur of Connaught||9 August 1935||25 November 1961||Appeared in the 1930s classic documentary film No. 6207 A Study In Steel which showed the production of the locomotive from molten steel to the finished product.|
|6208||46208||Princess Helena Victoria||16 August 1935||20 October 1962||.|
|6209||46209||Princess Beatrice||23 August 1935||29 September 1962||.|
|6210||46210||Lady Patricia||6 September 1935||7 October 1961||.|
|6211||46211||Queen Maud||18 September 1935||7 October 1961||.|
|6212||46212||Duchess of Kent||21 October 1935||7 October 1961||.|
Two examples, 6201 Princess Elizabeth and 6203 Princess Margaret Rose are preserved and both have operated on the mainline in preservation. They were named after the two children of Prince Albert, Duke of York (later King George VI), and his wife, Elizabeth, Duchess of York (later Queen Elizabeth, and after the king's death, Queen Elizabeth the Queen Mother). Princess Elizabeth Alexandra Mary (later Queen Elizabeth II) was seven years old in 1933 when her namesake was built, and Princess Margaret Rose was nearly five in July 1935 when her namesake was completed. At the time, they were third and fourth in line to the throne. 'Princess Margaret Rose' is owned by The Princess Royal Class Locomotive Trust and is on static display at the West Shed Museum, Midland Railway-Butterley, Ripley, Derbyshire.
|6201||46201||Princess Elizabeth||Crewe Works||Nov 1933||Oct 1962||28 Years, 11 Months||LMS Crimson Lake||Carnforth MPD||6201 Princess Elizabeth Society||Undergoing Boiler Repairs||Retube required following multiple tube problems alongside boiler and firebox issues. Possibly new boiler ticket aswell as mainline ticket.|
|6203||46203||Princess Margaret Rose||Crewe Works||Jul 1935||Oct 1962||27 Years, 3 Months||BR Crimson Lake, Late Crest||Butterley||Princess Royal Class Locomotive Trust||Static Display|
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