Hello all Please note: This is not a homework question. I work in Engineering. Firstly Thank you for reading my post. I am trying to learn a technique called Hallade which is used on the Railway to design curves. I have some notes (attached). The bit I fail to understand is on page 8. Three equations are presented:- 1) Sin (Alpha) = 4V/C 2) Sin (Beta) = Sin(2Alpha) 3) Sin (Beta) = 8V/C I understand how equation 1 was derived but I do not understand how equation 2 & 3 was derived??? I was wondering if anyone could help shed some light into how equation 2 & 3 was derived, please do not miss any steps. I have been working on this for the last few weeks and got nowhere so I really appreciate any help you can give me. Thank you for your help. Please note: i have been informed by a few people that equation 2 could actually be wrong and should be Sin(Beta) = 2Sin(Alpha) but either way i still dont undertsand how its dervied.