Yeah, my main concern was whether or not the paint is safe and non-toxic. I've heard about lacquer paint that seems to be used commonly for toys as apposed to enamel for example.
I saw this website based in England that looks good, they do a "Sky Blue" that looks good for the Thomas the Tank Engine, "Red" for James and "Light Grey" for the carriages, although the smallet they do is 225mL pots.
"Bright Colour range paints are blended from high quality acrylic polymers which can be used for both interior and exterior applications. The pigments used are non-toxic, light fast and produce a high opacity finish. On non porous surfaces the sheen and colour can be enhanced by using a primer coat or sealer. Available in gloss, semi-gloss and matt enamel finishes. As with all Spectral coatings products, when dry they conform to BS5665-EN 71/3 Toy Safety Regulations 1995- a certificate is available upon request".
http://www.spectralcoatings.co.uk