IEC 61991:2019 is available as IEC 61991:2019 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.

IEC 61991:2019 defines requirements applied in the design and manufacture of electrical installations and equipment to be used on rolling stock to protect persons from electric shocks. This document is applicable to rolling stock of rail transport systems, road transport systems if they are powered by an external supply (e.g. trolley buses), magnetically levitated transport systems, and to the electrical equipment installed in these systems. This second edition cancels and replaces the first edition, published in 2000. It is based on EN 50153:2014. This edition includes the following significant technical changes with respect to the previous edition:
a) replacement of several reference standards.
b) several terms and abbreviated terms are introduced;
c) special national conditions are included in annex