Simplify the following text for a Grade 10 native English-speaking person.
Original: Almost 70 years later , the design was used as the basis for a new rake of carriages built by the Ffestiniog - testament to the excellence of the original design .
Simplified: Almost 70 years later , the design was used as the basis for a new set of carriages built by the Ffestiniog Railway , suggesting how good the original design was .