The current northside red/brown/purple capacity is about 36,000 riders per hour in each direction. Completion of the Clark St flyover will increase this by 20% to about 43,000 riders per hour.
Additional improvements on the north side will give the CTA the ability to run 10-car trains on the Red line and 8-car trains on the Brown and Purple lines. This will increase capacity by another 25% to about 54,000 riders per hour.
Total capacity increase is 50% or 18,000 riders per hour.
This will mean a similar increase in the number of cars running during morning and evening rush hours which will require another large train yard, which the CTA plans to build at 130th St. (The yards at Howard, Kimball and 98th Streets are currently at capacity.)
The total cost of this has been estimated at $7 billion; $4.7 billion for northside work plus $2.3 billion for the southside extension and a new yard at 130th St.
In terms of major capital projects, this is the CTA's #1 priority and rightfully so. The only thing holding up work is the need to find money to pay for it.
See pages A-19, 20 and B-1 in attached
CCAC report.