What is Route availability?
'''Route Availability''' ('''RA''') is the system by which the [[permanent way]] and supporting works ([[bridge]]s, [[Embankment (transportation)|embankments]], etc.) of the [[National Rail]] network of [[Great Britain]] are graded. All routes are given an '''RA''' number between 1 and 10. A route availability of one (RA1) is the most restricted. 10 is the most open. [[Rolling stock]] is also given an RA (again between 1 and 10) and the RA of a [[train]] is the highest RA of any of the supporting elements. The RA is mainly about the [[axle load]] of the vehicle, although axle spacing is also considered. In practice it is the [[locomotive]] which decides where trains may operate, although many high capacity four axle [[Rail transport|wagons]] have high RAs when fully loaded. (When considering the operation of trains the [[loading gauge]] must also be considered.) {{transport-stub}} [[Category:Rail transport in the United Kingdom]]