Helix123

Continuing off of what RCJP posted, we can delve into the pro's and con's of trailered coaster trains. A trailered train will have just one set of wheels on every car except the zero car, which could either be the first car (GCI's Millennium flyers for example) or the last car (Arrow Dynamics looper trains) This is beneficial for two main reasons: 1. Having one set of wheels per train improves comfort and smoothness of the ride considerably, as it increases the distance between the car couplings and the wheel assembly. In essence, a trailered train operates with the minimum set of wheels necessary to constrain all non-desired degrees of freedom. (Think of the car as a see-saw. A trailered train pivots forward and backwards on its wheel assembly, and is kept level by the coupling in front. In contrast non-trailered trains are kept level by the additional set of road wheels at the front, in addition to the coupling between cars) By removing this redundancy, the train can better conform to the shape of the track, and will give a smoother ride. One of the cars must be non-articulating to constrain the pitch of the rest of the train however, this is what RCJP refers to as a ‘zero-car.’ 2. Trailered trains offer improved articulation compared to non-trailed equivalents, allowing more extreme track maneuvers, while simultaneously reducing wear and tear on track and train components. It’s often said that PTC trains ‘tear up’ a wooden coaster faster than other trains, and there is quite a bit of truth to this. PTC coaster trains are non-articulating, and the additional wheel assemblies cause additional wear and tear on the track. The front wheels may come off and slam back down at points during the ride, and this ‘bouncing’ creates areas of high stress and can even cause pitting of the track over time. It’s this ‘bouncing’ that contributes most to the reduced ride quality given by non-trailered trains. Cons: This is a real stretch, but one potential con of trailered trains is reduced mechanical redundancy. The Mindbender at Galaxyland suffered a terrible accident in 1986, where missing bolts in the wheels assembly caused a mechanical failure, resulting in derailment of the last car. The cars were modified from the original trailered design to non- trailered after the incident, the hope being that the additional wheel assemblies would create a backup in the event of a failure. It should be noted that this entire tragedy was the result of improper maintenance and inspection of the coaster trains prior to operation. Hope this helped! -Helix123 Note: I'm not even going into steering wheel assemblies, That's another beast entirely. And the wall of text would be scary.