Twenty B Class engines were built by Neilson, Reid and Company and numbered 440-459. A further 9 were built at the South Eastern Railway's Ashford railway works and given a jumble of numbers: 217, 13, 21, 101, 34, 17, 132, 186, 189. They kept these numbers under the SECR. When the Southern Railway took over in 1923 they initially gave the numbers an "A" prefix and later added 1000 to them. For example, 440 became A440 and then 1440 and 13 became A13 and then 1013. A few passed into British Railways ownership in 1948 and had 30000 added to their numbers but it is believed that only 31446 actually carried its number. All had been withdrawn by the end of 1951 and none remain.