Altering an Era in trainz 22

[Jersey pete]

I have a problem that i cant work out. I have built a layout using TransDEM but wish to change the time period to 1930's to1950's in Britain no matter what I try i cannot seem to get the era to work on my layout i have altered the region kuid but that hasnt worked and added the new kuid at the end of the kuid table that hasnt worked either, I would be grateful if someone could help me thanks