The Illinois Department of Transportation and Union Pacific Railroad will again be upgrading Illinois’ signature high-speed route, Chicago-St. Louis, for future high speed Amtrak trains, from April 16 through May 25.

The improvements for 110 mph service include the installation of new premium rail with concrete ties and stone ballast; upgrades to bridges, culverts and drainage; signal and wayside equipment installations and upgrades; and roadway-rail grade crossing improvements.

Most days, this work will lead to the substitution of chartered motorcoaches for Amtrak Lincoln Service (Trains 300-307) passengers at St. Louis, Alton and Carlinville.

The Amtrak Texas Eagle (Trains 21/321/421 & 22/322/422) will detour between Chicago and St. Louis for the same period, with alternate transportation in both directions between Joliet and St. Louis.

The temporary changes will allow Union Pacific’s Track Renewal Train crews to improve infrastructure to enable Amtrak service to travel at speeds up to 110 mph (177 kph), an increase from the current maximum of 79 mph (127 kph).

Illinois DOT and Amtrak are planning to preview higher speed trains in September 2012 from Dwight to Pontiac.