The dmu is being cleaned & serviced in the goods platform. When the new station is built, full passenger signalling will have to be installed. This view shows our attention to graduated curves. In real life, a C1 coach will negotiate a six chain radii curve but need the curve to be graduated at less than 5%. Those with a degree in maths will know how to calculate the change to a curve or gradiant using calculus. Railway vehicle & civil engineers use these calculations day in & out for platform & structure clearances. What is so critical is the behaviour of two vehicles next to each other so as to avoid buffer locking or damage to the connections. The worst curve on a railway is the reverse curve, or S bend on a road. My corridoor connections have to be wide enough to cope with our sharpest reverse curves. Now back to earth. Few!