The victim, a former CTA bus driver, was taken to Mt. Sinai Hospital in critical condition shortly after 9 a.m.
CTA officials say the federal credit union, located inside a CTA garage in the 600-block of North Pulaski, is for transportation workers. Officials say the robber or robbers got away with as much as $100,000.
Police say the worker was approached outside of the credit union office, possibly near a service entrance or the garage.
"That is a shock to me because we have security," said CTA employee Clifford Brown.
While there is security on the Pulaski side of the CTA garage, there is none on the back side off of Chicago Avenue.
Some CTA workers are convinced the robbery was planned or possibly an inside job because only employees would know about the credit union.
"A lot of people don't know about it. So I can't even speculate on what happened, if he was set up. You just never know," said Brenda James, CTA employee.
Witnesses gave police a description of the van they saw two offenders take off in after the robbery. Police caught up with a van that matched the description at a nearby gas station. Two men were taken into custody.
"If there was cash or guns in the van, they did let nobody see them bring it out. All I see them bring out was the two gentlemen who were in the van. There was no resisting arrest," said Larome Zrayer, gas station employee.
The red minivan belongs to Melana Collier. Her 20-year-old son was taken into custody, but she insists he had nothing to do with the robbery.
"Those cameras that they put up on the corners, it's a camera ... that points directly in front of our home and can show that my van has been sitting out in front of the house all morning," said Collier.
Collier confirms her son's cousin was also taken into custody.