By 1914 the entire Midland network was being operated by six basic engine designs: a Class 1 0-6-0 tank engine for light freight and shunting, Class 1 0-4-4 tank engine for light passenger work, Class 2 4-4-0 engine for general passenger work, Class 3 0-6-0 engines in tank and tender variants for mixed traffic and freight, and Class 4 4-4-0 for express passenger work.