Longest scheduled trip by single car unit ?
 

I saw one on YouTube, a 153 unit from Swansea - Crewe.

Do 153s still get the name "bubble cars" ?

Note. For the uninitiated the Class 153 Super Sprinters are single-coach railcars converted from two-coach Class 155 diesel multiple units in the early 1990s. The class was intended for service on rural branch lines where passenger numbers do not justify longer trains, or to boost the capacity on trains with high passenger volume.