How do you school a horse that ignores other horses passing it and maintains its own pace in a rail class?

A horse that maintains its own pace regardless of what other horses around it are doing is one of the most valuable qualities in a working western rail horse, and it is developed specifically through exposure to exactly the situations that produce pace changes and consistent correction of those changes. The specific situation to school for is being passed. In a rail class, faster horses will move past, and many horses instinctively speed up to stay with the horses passing them — a natural herd behavior that is actively counterproductive in competition. Clinton Anderson trains horses to be passed by having a helper on another horse work alongside and then move past at various speeds while he maintains a precise pace. Every time the schooling horse speeds up to match the passing horse, it is immediately brought back to the requested pace and the correction is as calm and matter-of-fact as possible. The reverse situation — horses falling behind — also produces pace changes. Horses whose companions slow down or stop often slow in response, and this requires the same correction: maintain the requested pace regardless of what other horses around them are doing. The number of repetitions needed to confirm a horse against pace contamination from other horses varies significantly by individual horse and by how strong the horse's herd instinct is. Horses with a strong herd orientation may need many sessions of dedicated schooling in this specific situation before the training holds in a class environment. Horses that are naturally more independent in the herd tend to generalize the pace-maintenance training more quickly. At shows, using the warm-up pen as a schooling opportunity for this specific skill — deliberately positioning near horses that are moving at different speeds and correcting any pace change — is more productive than using the warm-up pen only for forward schooling.