A train of mass 150,000 kg ascends a straight slope inclined at \(\alpha^\circ\) to the horizontal with a constant driving force of 16,000 N. At a point \(A\) on the slope the speed of the train is 45 m s\(^{-1}\). Point \(B\) on the slope is 500 m beyond \(A\). At \(B\) the speed of the train is 42 m s\(^{-1}\). There is a resistance force acting on the train and the train does \(4 \times 10^6\) J of work against this resistance force between \(A\) and \(B\). Find the value of \(\alpha\).