Used for the last few years in LA and NYC, making it's introduction this year in a city that actually has a name instead of an acronym, a BIKE TRAIN is a scheduled route (with stops and stations) for bicyclists to join up and ride as a group along a route.
I'm riding the train from Sewickley Starbucks at 0630, stopping at the Coraopolis Park-n-Ride (Route 51 and Thorn Run Road) at 0645, and the Nevile Island RMU Hockey facility at 0700. Arriving at PNC Park at 0750 and Market Square at 0800. It's your basic Sewickley-Moon to NorthShore-Downtown Express.
Here's Pittsburgh's Bike Train layout as of press time:
Click on any blue-cyclist symbol for a popup-tooltip that explains what Bike Train stops there (and when).