What makes a Pretzel click?

Pretzel's patented single-rail powered ride system originally used a three-sided length of channel iron with an insulated secondary rail placed within the recess. With constant hard use, the need for a stronger, more dependable track led to the change to T-rail of the type used for mining cars, modified by adding the insulated 'live' rail.
The main rail was the conduit of the neutral side of the circuit; the live rail was the 'hot' side.The 110vac current was transmitted to the motor via the trackwheel and contact wiper. Pretzel cars ran on 12 pound rail (12 pounds to the running yard) obtained from the West Virginia Iron and Steel Co. of Huntington, WV and sometimes purchased through the Morris Wheeler Co. of Philadelphia.
"In the early days, they used to take a 24-foot piece of track and bend it this way and that. When I came on in '46, I used to make a 6-foot and 3-foot circle and put live rail on the outside and live rail on the inside. So when you turn on the inside, the live rail is on the inside. When you go around this way, the live rail is on the outside. I’d make up the design and they’d go down there and put it together. We’d ship all the pieces and when they’d get there, they’d put them all together like a Lionel train. That was the thing with the dark ride; we go could into any old or used building and put a ride in there."

Standard Pretzel car undercarriage in production for nearly 40 years.

"Originally, that track was 1 X 2" channel iron and we had fiber washers in there. And we used a 1/8 by ½ inch strip in the side and put a bolt through there and insulated that. But that didn’t work out, that wasn’t heavy enough. We put that in Ramagosa’s ride. I went down there and worked all night. We finally got the ride going. Then we got the railroad iron where we got fiber insulators. We had a machine to squeeze the clips together to hold the live rail. We had to create the ¾ X 3/8  X 3/4 live rail, cut 1/16"
short to join together with the bond plate. Then we'd mill it out where it fit into the clip. The bending machine used three rollers and could bend as tight a curve as you wanted. We'd make all of that by hand at the shop; bend the track, weld the clips onto it. We even wound our own springs. When I started full-time, that's when we went to the standard track sections, just straights and six-foot radius half and quarter curves. That did away with all those odd pieces."

Pretzel's spare parts catalog was a board-mounted display of every component of the undercarriage of the car, including axle, bearings, trackwheel, yoke, drive wheel, contact wiper and crescent, motor mount and transmission casting, drive ratchets, pawls, gears and hardware. Wheels and other parts were finished by the L. E. Hettinger Machine Works. "Louie" Hettinger's shop was right next door to the Pretzel building and was eventually acquired by the company. The heavy drive gears were specially produced for Pretzel using a custom tooth spacing and pitch. The large Pretzel shapes on the sides of the cars were sand cast at a local foundry, then finished and painted at the Pretzel shop. Wax Brothers, a furniture upholstery shop, made the seat cushions for the rides, and the cars were spray painted by Boswick's auto body shop.

Most makers of dark ride cars, such as Traver/Chambers and Allen Herschell, generally used the method of powering only the right-hand rear wheel while allowing the left-hand wheel to turn freely on its axle. This compensated for the difference in the turn radius between each of the wheels when the cars went into curves. But cars such as Traver's, with rubber-tired wheels, would experience more wear on the driven wheel.

Although Pretzel's initial patent indicated a similar design, almost as soon as they went into production this was changed to a dual-wheel differential. Two five-spoked ratchet plates were affixed to the gear-driven axle which interfaced with a spring-loaded drive pin located within each wheel. With this arrangement, the outer wheel on a turn in either left or right directions was free to rotate at the faster speed necessary to negotiate the larger outside radius. The torque would be shifted to the inner wheel at the shorter inner radius.

When the car moved onto straight track, the speed of the wheels would equalize and the drive pins would engage the two ratchets, powering both wheels together. This, plus the use of wide steel casters, resulted in more balanced wheel wear.

During a turn, the slipping of the drive pin against the ratchet teeth in the outer wheel, which was then turning more rapidly than the axle, gave the Pretzel cars their characteristic clicking sound.