Silverton Train

Hi, Andy:
First of all, you are thinking of the three K-28's in service on the Silverton Branch in the 1960's and 70's. It can be confusing at first glance sometimes because of the train numbers assigned to the two sections. They are (first section) #461-462 and (second section #463-464, all locomotive numbers from the K-27 class.
The answer to the first part of your question on the number of cars is as follows.
By 1967, the roster was completed with 21 cars assigned for daily service on the Silverton train's two sections. One was an 11 car set and the other was a 10 car set. If a private charter car was used on a given day, the two sections each ran 11 cars. The private cars always ran on the first train, and when there was no private car, the first section carried 11 cars.
In the early 1970's, the D&RGW began the campaign to rebuild the old wood coaches in steel. By the time the last two were rebuilt with steel, the cars were heavy enough that the K-28-s could only carry 10 cars in normal conditions, so a coach was usually set out and left behind. One engine could still barely handle the tonnage of 10 regular cars and a private car, but an 11 car consist with the new steel bodies was very hard to start on grade. Besides being very very hard on the little 470's.
I believe that the D&S has run 12 or even 14 car trains with the 480's, and now likes to restrict the 470's to 7 cars.
Mike