Video supplied by BART shows the kind of work they'll be doing to replace 1,000 railroad ties and 3,000 feet of rail in desperate need of repair.
During the construction, commuters can use a free bus bridge.
This may be the first of many construction projects over the next couple years.
"The system will turn 45 years old in the next couple of years," said Paul Oversier with BART. "And there is a lot of work and investment that needs to be done if we are going to continue to operate at a high rate of reliability, close to 90 percent."
Work is expected to be completed by August.
Construction will not affect the trams that take you to Oakland International Airport.
The construction dates in April do not conflict with any Oakland Athletics games.
Officials did say they might adjust construction dates for any special events such as the Golden State Warriors playoff games.
Click here for full details from BART on the service disruptions.