Abstract: A monolithic protective waterproofing system for light rail and intermodal class I railroad bridges comprehends a multiple layer product installed in-situ. It includes a sprayed on primer, a sprayed on membrane having a thickness of between 60 and 120 mils, a second sprayed on layer of membrane having a thickness of about 20 mils that is utilized as an adhesive that is rapidly covered with a resilient mat having a thickness of between approximately 6 and 12 mm, a second layer of a sprayed on primer and a top coat of sprayed on membrane of approximately 30 to 50 mils. Both the product and method of installation are disclosed.