Hornby's made a few attempts at the kiddie market over the years, but apart from Thomas and (sort of) Railroad, none of them seem to have really stuck.
My suggestion for a range like this would be to start with something with more play value - a caricatured Class 66 with a couple of container wagons and a container crane to enable loading and unloading, maybe a container lorry. Expand the range with playsets like a dockside (with container ship), a scrapyard (with open wagons), oil depot (with tanker) and other industries along those lines. Include figures as well. This would enable kids to actually play with the trains, rather than just run them round and round, and it would be educational. By sticking to modern image, they could produce the same items in several liveries for different markets. The aim would be to give the kids something to play with while nurturing an interest in real life railway operations. Maybe later add passenger trains, stations etc. As with Marklin, maybe make it remote controlled to make shunting easier and more realistic.
It seems odd that Hornby is going for such a basic set when Brio, Tomica and Marklin have all produced toy trains along similar lines with much larger play potential.