WOODBURY - The Long Island Rail Road is making changes to ensure the safety of its commuters in the wake of the fatal Metro-North derailment.

There are nine critical curves on the LIRR system. On Monday, the MTA identified seven more major curves on the system.

The LIRR currently has automatic speed controls to slow trains down on two-thirds of its trains. The other third, which operate between Ronkonkoma-Greenport and Speonk-Montauk, do not have speed controls. The MTA says it will enforce posted speed restrictions on the curves with an automatic speed control system.

The Federal Railway Authority is mandating that Positive Train Control, a GPS type of system that monitors and controls train movements, be installed by 2015 across most of the country.

Positive Train Control will cost $1 billion for both the LIRR and Metro-North. The MTA is applying for federal grants to cover that cost.