The transitions from the end of one rail to another - the rail joints - are a very sensitive area. There are often points where one profile transitions into another, and these profiles have to be at the same height. Controlled compression and flash welding are used to position the rails at the right height and join them together. The left and right running edges can be manufactured according to customer specifications.
Tracks also require rails to be electrically insulated using insulated joints in order to guarantee reliable signaling. Temperature differences throughout the year of more than 40° make this a challenge that requires a lot of technical expertise