The Making of Princess Anne

Princess Anne was in our opinion one of the most handsome locomotives ever to grace L.M.S. metals. Its short time in service in 1952 gave us only six weeks to admire its impressive construction.

A very impressive handsome locomotive.

It started life in 1933 as the third Pacific in the L.M.S. Princess Royal Class, designed by William Stanier. It differed considerably from the first two prototypes, 46200 The Princess Royal and 46201 Princess Elizabeth. Princess Anne was built as an experimental turbomotive locomotive, which proved to be a great success and ran in this guise for many years, but the L.M.S. directive in the early 1950s, to standardise on parts, resulted in its being rebuilt as a traditional Pacific.

The L.M.S. at this time had moved on from the Princess Royal Class and were constructing the superior Princess Coronation Class. This resulted in Princess Anne being a hybrid of the two, incorporating a Princess cab and firebox and a Coronation boiler and cylinders. This sounds simple, but for a modeller, the two pieces don’t fit together as simply as it sounds.

After only six weeks in service, Princess Anne was involved in the Harrow and Wealdstone railway disaster and received such serious damage that it was deemed to be beyond repair. It was in service for only six weeks, yet we believe it to be a locomotive worthy of remembrance.

The Parts

We used the Hornby Super-detailed Princess Royal as our basic model, to which we attached several parts of a Hornby Princess Coronation body, which we found on ebay, along with a Mk1 4,000 gallon, 9 ton capacity Stanier tender body, which was originally constructed to partner the rebuilt Royal Scots. Princess Anne ran all its life with one of these tenders; it never had a high-sided 10 ton Stanier tender.

Note the Stanier Mk1 4,000 gallon 9 ton tender and stepped footplate.

The Build

After removing the smoke deflectors on the Duchess body, we found the smoke pipes needed enlarging.

Due to Princess Anne using the larger Coronation cylinders, the footplate is higher than that of the Princess. The mechanics of the time solved this by overlaying the Coronation footplate on the Princess footplate. We did the same, hence the step just back of the middle drivers.

Princess Anne had a Coronation chassis which accommodated 6’9” driving wheels, equally spaced, yet it ran with its original 6’6” wheels, so on our model, with a Princess chassis and the spacing of its front drivers greater than the gap between the centre and rear drivers, this had to be corrected. We re-drilled the chassis and moved the pairs of front drivers back. Skill, patience and trial and error were required here.

Coronation connecting rods and valve gear were ordered from Hornby, as the original Princess set no longer fitted.

Note the bulbous front end and Coronation cylinders and smoke pipes.

The Boiler and Firebox

We joined the two boiler parts together in front of the Princess firebox, but this also necessitated the slicing of the Coronation boiler at the first boiler band, as it needed realigning. We cut the two bodies too long and we also cut the footplates 1 cm longer than the bodies, to strengthen the join, and avoid a straight cut through the model. Trial and error and lots of dry runs at overlapping the two boiler sections is the only way of guaranteeing success. We drew a line depicting the total length of the engine on a sheet of paper and kept placing the two halves on it, checking continuously as we filed the two halves nearer together. Both the Coronation and Princess class vary in length and are slightly different from Princess Anne. A Princess locomotive is 74’4” long, a Coronation locomotive is 73’10” long, the rebuilt Princess Anne is 74’ long. (Details of locomotive dimensions can be found on the web).

We found the Coronation boiler to be slightly too wide to fit perfectly against the Princess firebox, but gentle filing and filling corrected the discrepancy. After ensuring the footplates were straight, careful filing of the boiler profile completed the join.

Bits and Pieces

The Hornby Princess chassis needed remodelling to accommodate the fitting of the Coronation Cylinder block. We concluded that a permanent fit was the only way to reseat it, so a tight fit and glue was used rather than screws.

Footplate detailing, such as sand boxes and oil valves, are positioned differently to both the Princess and Coronation locomotives. Check out pictures of Princess Anne on the web for accurate reference.

The nameplate is placed over the front drivers; to centre the name vertically over the wheel centre requires repositioning of footplate detailing.

Finally Princess Anne ran with a Mk1 Stanier 4,000 gallon 9 ton tender. We found a spare Royal Scot tender body on ebay and it fitted perfectly on the Princess-supplied tender chassis.

As with all our models, we have included real coal in the tender, and we strategically placed footplate staff in the cab to give them maximum visibility. We find these figures disguise the excessive gap between the engine and tender, which is unavoidable on OO models. Cab doors also close the engine to tender connection.


This model is more difficult than it looks. It is more than sticking a Princess Cab to a Coronation Boiler. Much thought and patience is required, so we would only recommend dedicated modellers take on this project. Observation is a necessity and research is encouraged. But we are sure you will agree the result is a fine locomotive. We hope we have been of help and wish you fun and satisfaction with your modelling.

For any further help and advice please contact us.

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