User blog comment:Djjd47130/Electric Collector III - How long is this going to take?/@comment-31595794-20180311220543

Hmmm... I'm not sure... all I know when I did this, from PF change game layout... I was automatically completed all Steam, Diesel and Electric all in one go in one day... I was like yike... so many completed award XD ... only had Maglev and Hyperloop, two left only.... for me get final award for both...

So I'm not sure... but do know... often is get more friend to list, so u can have more found missing list from ppl, or doing achievement or contractors or as you said buy them when they are in the shop...

That is what I can think of to answer your question.