Question About this Thomas Version

I just received this new Thomas and it seems different from all the other Thomas's I have seen. There looks to be holes (circled in picture) that go right through the chassis that look like they could hols another set of wheels. Anyone know their purpose or what they are used for?

Not sure why, something to do with packaging maybe? They appeared on the re-designed model in 2012. Other external features to note include the front splashers moved forward of the front wheels, longer boiler, shorter smoke-box, lamp vanished, the shadow between the splasher and the tanks changing from black to blue, and the slots in the coal-box coloured in black. Also a new face.