The reason why the spin-off was never taken further seems to be because HiT Entertainment did not want it to conflict with their own series Bob the Builder when it bought the rights to Thomas the Tank Engine & Friends in 2002.
A main character of the show, Oliver, was originally going to be named Buster, a name used by another character in the show.
A character named Nigel was planned for the series but was dropped during production
The reason why this spin-off was never taken further seems to be it, is because HIT Entertainment (Now known as Mattel Television) didn't want it to conflict with their own series, Bob the Builder when it bought the rights to Thomas & Friends in 2002.