Several times in this life I have seen this sort of thing happen, and in most cases they're usually within the United Kingdom. Here is a short series of blogs about projects that were stopped before they could begin or releases that never came to fruition:
THE DIDDLEYS (2003)
When Thomas the Tank Engine still ruled the rails (and still in model-form), and long before Chuggington came to be, Silverglint Entertainment tried to get in on the act by what it seems like an attempt to merge two of the most popular interests for boys - namely, steam engines and superheroes - while also trying to match Pixar in terms of CGI animation.
that lonely little book in a charity shop, or see if the Diddley-themed engines are still at work at the Brooksland Miniature Railway in Sussex, which must have been created to help promote the series further...then again, it's been so long, no one seems to know whether the park is still open today.
Ah well, that's life - sooner or later, things get derailed, quite literally =P