Among the various people getting on and off the bus was a man who in an unprovoked attack, launched into a knife attack on two other people.
One of them, an 18-year-old man, suffered major stab wounds which were originally thought to be life threatening. He is now in a stable condition in hospital.
The other victim, also 18, suffered a minor stab wound to the stomach and a small scratch to the face.
Just a short time after fleeing the scene, the knifeman boarded another bus – the number 47 heading out of city – where he was heard by a fellow passenger talking about what he had done.
He then raised the alarm and police boarded the bus a few minutes later on Pershore Street, where the man was arrested following a violent struggle during which an officer was punched in the face. Three knives were seized.
The 22-year-old was arrested on suspicion of wounding and was taken to hospital where he currently remains under police guard until he is in a fit state to be questioned.
Officers are now appealing for witnesses to come forward and speak to them.
Detective Inspector Justin Spanner, from Force CID in Harborne, said: “This was a very fast-moving situation in an busy part of the city and there were lots of people around.
“I want to hear from anyone who saw any part of the incident, especially those who may have seen the attack itself, who witnessed him running away, or who was on the second bus.
“If you have not yet spoken to us, please give us a call on 101 as soon as possible.
“This was a scary incident for everyone involved but thanks to some swift action by the members of the public who called police, we were able to get the situation under control very quickly.
“At this stage we’re not looking for anyone else in connection with what happened.”