Is this your model? https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=2019519669&searchtext=Clas+66

Why did these disappear in the first place?

Apologies it was only available to friends not public. Its the default setting. Should be visible now.

@Cibaris Could we please get the Class 66 in EWS livery back as well? It's my favourite livery carried by the class.

Cibaris some people have done that but It didnt work. I tried it last week and just resorted to using TPFMM from now on

You need to remove old Class 66 by going into enable mods then enable exactly the same new mod as per lookastdu says. Follow his instructions which are very easy. The new mod is identical to old mod. Sienous, all mods were uploaded and none are missing. They have worked for almost everyone so follow instructions.

Wow a whole load of these mods were removed and now I can't load my savegame... not happy

Yep, I cant remove it from my savegame because It was one of the engines I had in use. Not Happy, Not happy at all

@TrainyUK Was that the EWS one? Try the class 66 replacement mod and see if that works [although it didn't for me as it had the EWS 66 error] as it has for some.

Lookastdu it doesnt work at all, One of the trains I had has been completely removed and has not been reuploaded rendering the map useless

How to probably fix save (tutorial for people with much less knowledge about TF, like me):
- subscribe to this mod
- run game and in menu choose "load game"
- choose you save, below you should have list of mods and error with lack of "class 66" mod
- a little bit above, to the right, there is button with "+" on it; click it
- on the list search the "old mod" with error - disable it
- now search the "new mod" (that you have just subscribbed) and enable it
- try to load game

For me it worked, but I have not used class 66 train anywhere on map actually.

And in future - use TPFMM (Transport Fever Mods Manager, google it).