some information and thoughts:
The very long, box car like car that got dubbed "the elephant car" seems to have some elements similar to one of the Sumpter Valley excursion cars of which I have seen a photo. It is long and the underframing looks like that of a passenger car.
The Montarey & Salinas Valley (later Nevada Central) box car is now in the collection of SPCRR. They built a T-111 billboard subsitute and traded it for the old, old car.
I hear that the Billmeyer & Smalls box car was cut into pieces when it was moved because the purchaser did not have a truck or trailer long enough to take it in one piece. Gads, that car dated from the 1870s!!!
I remember looking over the cars years ago. One of the box cars had only a "four-stick" underframe. Only center sills and side sills -- no intermediate sills.
There were three passenger cars there. All came from the E&P. The two Colusa and Lake cars (baggage car and a coach made into a combine) and a B&S combine. All of these were on freight car trucks. All of these were apparently without trucks when the bodies were scooped up by "Dobby Doc" a collector of abandoned artifacts in Nevada and maybe elsewhere in the west. The Dobby Doc collection ended up at the Last Frontier hotel in Las Vegas and then the railroad equipment later went up to the Gold Strike casino near Boulder City. These three cars and the 2-8-0 are now part of the collection of the Southern Nevada RR Museum (state operated).
Brian Norden