Complex sentence: Although at parts its gradient was as steep as 1 in 7, Campbell managed find a route with a maximum gradient of 1 in 14, but a stationary engine would be required at the top of this stretch to pull the railway carriages up the incline.
Split into simpler sentences: Although at parts its gradient was as steep as 1 in 7, Campbell managed find a route with a maximum gradient of 1 in 14. A stationary engine would be required at the top of this stretch to pull the railway carriages up the incline.