sentences:  After that the Works concentrated almost exclusively on tank engines of the 0-6-0 and 0-4-2 types, saddle tanks at first, then side tanks (such as the 517 and 645 classes).They were often turned out at remarkable speed.Many of the 0-6-0 saddle tanks were rebuilt as pannier tanks in the time of Churchward, at the time they were fitted with Belpaire fireboxes.