Freight Rail Assistance and Investment to Launch Coronavirus-era Activity and Recovery Act of 2020 or the Freight RAILCAR Act of 2020 This bill establishes a new tax credit for the replacement and modernization of qualified freight railcars. Specifically, it allows a credit for 50% of the sum of the qualifying replacement or modernization amount, the qualifying scrap amount, and the qualifying railcar facility and technology modernization amount. The bill defines qualified freight railcar as a freight railcar that meets significant improvement requirements for capacity, fuel efficiency, or performance.