The Metropolitan Line of the London Underground, which opened in 1863, was in need of steam locomotives that were fitted with a condensation device to reduce the amount of steam emitted. Since initially three-rail track was laid, the line could initially be operated by the broad-gauge metropolitan class of the GWR. However, since the GWR ceased operations after just a few months, standard-gauge Great Northern locomotives had to step in spontaneously.

In search of their own type of locomotive, the Metropolitan Railway received an offer from Beyer Peacock for tank locomotives with a 4-4-0T wheel arrangement, which should be available within six months and were offered at a price of £2,600 each. They were based on a type that had been developed for the Spanish railway from Bilbao to Tudela. Further orders for identical locomotives came from the LNWR, LSWR and the Midland Railway.

Modernized version with driver's cab

Locomotive Magazine, December 1896

Between 1864 and 1870, 40 examples were initially built for the Metropolitan Railway, which were later to be designated Class A. They did not have a driver's cab, as this would have led to heat build-up in the conditions when driving through the tubes. Almost all of the exhaust steam from the cylinders was fed into the water tanks, preheating the feed water. Initially coke and later high quality South Wales coal were used as fuel, while firemen were trained to produce as little smoke as possible.

Between 1879 and 1885, 26 more of the later class B followed. It had identical cylinders and wheel dimensions, but slightly higher boiler pressure and larger reserves. The wheelbase was reduced and the bogie was no longer in a bissel frame, but was hung up like an Adams axle. These measures improved running characteristics and weight distribution.

Conversion to tender locomotive, Cambrian Railways

Locomotive Magazine, February 1916

As early as 1880, modifications were made to the existing locomotives. These included higher boiler pressures of 150 psi instead of 125 and 130 psi, respectively, 17.5 inch diameter cylinders instead of 16 inch, and 5 foot 10 inch diameter drivers. Driver's cabs were fitted from 1895, even if these were not well received by the crews. The firing of oil was tested on one engine, but not pursued further due to the high price of low-smoke oil.

When the Metropolitan Line was electrified in 1905 and 1906, the surplus locomotives were sold. They reached different parts of the country and were used as shunting locomotives or in front of construction trains. Some pieces even survived into the forties. Of the six units that the Cambrian Railways had acquired used, two were converted into tender locomotives. 

In 1875 the Natal Railway Company ordered a heavier third engine from Kitson and Company in Leeds, where the “Durban” had been built ten years earlier. With a 4-4-0T wheel arrangement, the new locomotive was significantly heavier than the first locomotives and had a cab in addition to conventional lateral water tanks. It arrived in Durban on January 10, 1876 and was christened “Perseverance”. It had three almost identical sister locomotives that were built for the Trinidad Government Railway.

Before the “Perseverance” entered service, the Natal Government Railways had already been established and so on 1st January, 1877 the locomotive became government property for a payment of £40,000 along with the other two locomotives and all other properties of the Natal Railway Company. For a short time it was used together with its predecessors on the line and mainly transported stone from the quarry to the port. With the gauge change, the use of the “Perseverance” on the rails came to an end, but it remained in the possession of the railway company. They used it in their workshops in Durban until 1887 to drive a sawmill and then scrapped it.

For operation between Berlin and Potsdam, a tank locomotive was needed that ran more smoothly than the T 5¹ at higher speeds. The solution was to do without the trailing axle and instead to use a laterally sliding bogie at the front.

30 of this variant were procured from Henschel and six more from Grafenstaden, which were delivered in 1899 and 1900. Despite the same size driving wheels and an unchanged top speed of 75 km/h, the running smoothness had improved significantly above 60 km/h. The disadvantage of the missing trailing axle, however, was the worse running properties when reversing, which meant that the T 5² was used on the Ringbahn (Berlin belt railway) instead of on the planned route. The special feature of the last two examples was the use of a Schmidt-type smoke tube superheater. Although no further production took place, they were superior to the conventional engines and also represented the first superheated locomotives in Prussia.

One of the two engines that were delivered from the factory with a superheater

Die Lokomotive, January 1924

Of the 20 engines that existed in 1923, two were redesignated two years later by the Reichsbahn as the class 72⁰ and retired the following year. In 1941, two examples came from the Eutin-Lübecker Eisenbahn-Gesellschaft to the Reichsbahn, which were identical in construction to the T 5² and had already been converted to superheated steam. They were given the same numbers as the previously retired engines. One of them was able to stay with the Deutsche Reichsbahn in the GDR until 1955.

In 1849 the GWR manufactured the “Corsair” and “Brigand” saddle tank locomotives for passenger services on the steep and winding South Devon Railway in their own workshops in Swindon. Since the bogie could not be moved sideways, the first coupled axle was not given wheel flanges. The “Corsair” still had a sledge brake, the “Brigand” received a shoe brake on one wheel.

“Ovid”

Locomotive Magazine, June 1902

As the operation of the South Devon Railway was finally handed over from the GWR to a specially founded company, the two locomotives were used on other lines. A further 13 locomotives were ordered, but the production of these was handed over to Hawthorns'. In these, the diameter of the driving wheels had been reduced by three inches.