Once of the most challenging things on the Viewliner has been how it'll negotiate curves-- more specifically, how the cars and their diaphragms between them move and have enough clearance to do so. 

The original Viewliner had an interesting set-up between the cars. While most modern passenger (and even the Disneyland Monorail) have flexible and moving diaphragms, the Viewliner's are rigid; you can see how they are a piece of sheet metal mounted to the front each passenger car, and they move within a cavity of the car in front of it. 

Photo: Gorillasdontblog

To accomplish this on the miniature was quite a challenge, especially when the model is going to be taking tighter turns than the prototype. In the picture below, you can see the diaphragms in light green intersecting into the passenger cars. This is the tightest curve designed, so if everything clears here, it should in theory work in the physical world. Based on where the wheel trucks are mounted, I took that center point and figured out where to chamfer the diaphragms based on the pivot point. This helped gain more room in the passenger cabin and keep the lengths and proportions of the cars and their windows prototypical. 

Below you can see how the diaphragm from following car (not yet seen) in grey will nestle into the previous car. The chamfered edges will mostly be hidden and may be barely seen when the train is a on a curve. 

Above is the first few phases of working out how the passenger car wheel trucks fit within. How the cars will be mounted to them is still being figured out. The light green bounding box helps figure out the clearance of the truck swiveling. These trucks are actually pilot trucks from a Bachmann N scale 4-6-0. 

While the diaphragm design seems to work for all the passengers cars, getting the transition to work between the locomotive and the first car proved to be tricky. The biggest problem here is the motor block for the locomotive actually sticks out of the body and into the cavity where the diaphragm is suppose to move within. 

The solution to this problem is to flip where the cavity goes--the first car will be the only car to have cavities on both ends. This way the diaphragm actually hides the motor block and still allows movement. The design compromise here is the first passenger window had to start a little further back than the prototype, but the car's design otherwise stays the same. A tiny change I'm willing to live with. 

Interestingly enough, most people don't notice that the passenger cars are not symmetrical! This is due to the rigid diaphragm design. 

In this photo cropping from Davelandweb, you can see the Viewliner passenger cars were not symmetrical looking from a side elevation

Top view showing how the first car (and only the first car) will have two cavities for the diaphragms from the 2nd passenger and the locomotive will protrude into.

I've been experimenting with super capacitors and how they can improve a model locomotive's performance. Think of it as a "digital flywheel". N scale locomotives have hard time with even the slightest unkept track, so experiments are underway with a 5.5V 0.1F super capacitor. I've chosen a super capacitor versus a regular one because it can hold more current for the size and size a premium on the Viewliner. The trains will never go backwards and to keep the speed realistic the voltage is kept low so this capacitor is perfect. Should provide a few seconds of coasting when the power is cut, allowing much smoother operation. 

Super capacitor hastily soldered on for testing. 

If all goes well during the testing phases with the motor under load, the capacitor will be implemented. I've already started designing the void where the capacitor will go. The nose of the Viewliner should do nicely! 

And here's an overall view to wrap up the update. The locomotive continues to get tweaks and adjustments and it continues to get closer to finishing. Figuring out the diaphragms was a big step in getting it closer!