The Relationship between the CENELEC Railway Signalling Standards and Other Safety Standards.pdf
Although there are many different international, European, Japanese and
US safety standards, these standards coincide in many general aspects and
concepts. However, there are several differences in detail, e.g. while the
TFM, THR and MTTHE concepts are very similar with respect to setting
safety targets, the verification process for assuring that the targets are met, differs.