Making Interurban cars in N scale is not so difficult. If the 3D drawing is well made, you only have to make some adjustments, deleting or thickening some details too small to print, like rivets or small handrails. And you have to adapt the inner shape of the car body to the Tomytec drive of your choice.If all is well engineered, you will recieve your 3D printed car body from Shapeways and it will directly snap over the drive and stay in place. The paint job is a little tricky, but otherwise it's done.
Modern LRV are not of the same shape, they are articulated, they are in fact 2 or 3 cars permanently coupled together. And if none of the Tomytec articulated drives fits, you have to build something on your own.
As N scale model I chosen the Siemens S70. Because I had already made the car in HO, and because its one of the most build in the USA. And because it is running as multiple unit: I wanted to make three Siemens S70.
I will not talk here about the headache I had, just to say you that is was not simple. But the 3 cars are now in the assembling line. A first beta car was build and painted before for a well known trolley connoisseur from California.
The main hurdles are the building of an articulated frame, with two modified Tomytec TM-TR01 drives as A and B units, and a custom build C unit made from laser cut styrene parts. The car with 2 motors and all wheels capting current is powerful. A three car Multiple Unit is just tremendous.
But you need fine and calm fingers, for making the folded paper bellows, for soldering the fine wires connecting A, C and B unit, for masking and painting, for all
Two cars will recieve the red paint scheme of the San Diego MTS, with N scale decals made by Custom Traxx. One car will recieve an all white paint scheme, in order to be decorated later - after the meet - as an Utah Trax from Salt Lake City.
Here comes the "Finishing Kit" for the Siemens S70 LRV, it contains: tinted side windows, incurved clear windshields, 2 ready-to-mount flexible bellows and 14 micro screws. 
Making Interurban cars in N scale is not so difficult. If the 3D drawing is well made, you only have to make some adjustments, deleting or thickening some details too small to print, like rivets or small handrails. And you have to adapt the inner shape of the car body to the Tomytec drive of your choice.If all is well engineered, you will recieve your 3D printed car body from Shapeways and it will directly snap over the drive and stay in place. The paint job is a little tricky, but otherwise it's done.
Modern LRV are not of the same shape, they are articulated, they are in fact 2 or 3 cars permanently coupled together. And if none of the Tomytec articulated drives fits, you have to build something on your own.
I will not talk here about the headache I had, just to say you that is was not simple. But the 3 cars are now in the assembling line. A first beta car was build and painted before for a well known trolley connoisseur from California.
Two cars will recieve the red paint scheme of the San Diego MTS, with N scale decals made by Custom Traxx. One car will recieve an all white paint scheme, in order to be decorated later - after the meet - as an Utah Trax from Salt Lake City.
I downsized my Siemens S70 HO drawing to N scale and put it on two cannibalized Tomytec drives and a custom made central floor section. Making the paper bellows in this scale is a little bit tricky, as doing the paint job.
Today was a paint shop day. Warm spring weather allows to speed up the process.
More roof details for the HO scale model of the Siemens S70 LRV: corrugated sheeting in the center part, cable channels on both sides left and right. 
