Thomas the Tank Engine Wooden Railway.
We got our first train set when Biggie was two years old. Biggie was about three when we won a huge pack at an amusement park. It was quite exciting since the sets are expensive and we were happy to add to our then-meagre collection. We became big fans of wooden railway and have added a few bits to our set on birthdays or Christmas.
Biggie (8 years old) still enjoys making complicated layouts when he is roped into playing with Little Guy. I continue to be impressed by the layouts Little Guy comes up with on his own. This type of toy encourages fine-motor control and logical thinking (educational!).
In terms of investment toys I really recommend wooden railway. It will definitely last to pass onto our grandchildren. It's seems fairly indestructible. My kids throw the parts into the box, stand on them and sometimes forcibly click them together!
We do occasionally watch Thomas the Tank Engine on television. We also have a few of the books. My kids seem to enjoy playing with our trains and making up their own adventures. This makes me so happy.
All three of my boys (husband included) have given this new train bag the thumbs up! I like it since we are train fans without having to profess our love for Thomas.