HB 4662 establishes a grant program under the Texas Department of Transportation to provide financial assistance for short-line railroad improvements. It authorizes the department to distribute grants to rural rail transportation districts and short-line railroads for track and bridge replacements, rail capacity improvements, and rail restoration projects. To be eligible, projects must increase public safety, promote economic development, or reduce traffic congestion. The bill requires at least 10% of the total project cost to come from non-state sources and prohibits the use of state highway funds