Mario, sorry I can't help you with your question, but I was wondering if you might help answer a question for me?
Over on the topic where I had drawings of a North Pole Central FT, I proposed using a FT locomotive with the NPC cars, but was curious how an FT would look with the 027 North Pole Central passenger cars as I have not seen them together. Looking at the Grand Central Express set in the 2012 catalog, I can see the NYC passenger cars are more detailed than the North Pole Central cars as they have detailed interiors, and it appears the NYC cars are about 1 inch longer at around 13"(the 2-pack is listed as 26" long) versus 11-3/4" long for North Pole Central cars. I didn't know you have an FT engine.
Could you post a photo of your FT locomotive with some North Pole Central passenger cars? It would be interesting to see how they look together.
Back to your question, after reading the features in the catalog descriptions, it sounds the engine and cars are pretty similar between the 2003 NYC Limited set and the 2012 GCT Express set. The 2003 set is listed as 51" long, and the 2012 set is listed as 52-1/2" long, but I'm not sure about the accuracy of catalog measurements.