On June 2, 2015, four trains were operating on Smiler. A decision to add a fifth train to the ride was made because the park was rather crowded that day. The newly added train was sent empty onto the coaster, but the empty train lost speed as it went through the course and stalled before reaching the end of the ride. Having an empty train stall out is not that uncommon for a couple of reasons. Lacking the weight of a full train, empty trains lose speed more quickly than full trains. And to make matters worse, a newly added train has cold lubricants on the wheels and axles, and those thick lubricants also tend to slow the new train's speed down. A typical coaster train will take several passes through the ride until it warms and reaches its normal operating speeds.
The empty train was manually pushed to the end of the course by the park's engineers, and was sent out of the station, empty again, for another test run. The empty train slowed and got stuck again, but the engineers were unaware of the stall and handed the ride back over to the coaster's operators. The empty train valleyed and came to rest in an area not visible from the operator's location in the station.
©2019 Joel A. Rogers.