The CTA wants riders to know how and why delays happen on its trains and buses, and it's promoting a new website to tell them exactly how it happens.

The “When things go wrong” page, launched Wednesday, answers questions -- from why Red Line trains get rerouted “over the top” on elevated lines downtown to how buses get bunched up. The specific questions were culled from social media posts riders sent over the past year.

“[CTA President] Forrest Claypool made a heavy push to get the CTA on Facebook and Twitter,” says CTA spokeswoman Lambrini Lukidis. “Over about a year, we were able to track what sort of questions riders ask.”

Some of the questions are generic, such as “What causes bus delays?” But others shed light on public transit jargon.

One question asks why some buses seem to drive slowly or purposefully miss green lights. “In the event that all the stars and the planets align in such a way that traffic is way lighter than normal..buses can get ahead of schedule,” the site says. “We refer to this as ‘running hot.’ [This can] create a big gap in service and, potentially, one that’ll slow down a following bus so much that it ends up getting bunched with its follower."

Lukidis says the site is meant to be earnest answers to questions riders may not always like the answers to.

“It’s not meant to be canned responses, but it’s a better way to have people read up on questions they may have,” she says. “It’s a way to prevent people from getting frustrated, or at least understand why.”