Forum users may not be aware that there is an excellent step-by-step guide with 77 photos by Pete Hill showing his conversion of the Bachmann BR Standard 4MT 4-6-0.
This can be found in the Technical Papers under the Manual Sheets section of the Members Area:
https://emgs.org/wp-content/uploads/2024/07/Bachmann-BR-Standard-Class-4-conversion-to-EM.pdf
This conversion is similar to that for the BR 4MT 2-6-0.