; (2) make available explosives detection canine teams to all modes of transportation, subject to the requirements under section 1968, to address specific vulnerabilities or risks, on an as-needed basis and as otherwise determined appropriate by the Secretary; and (3) consider specific needs and training requirements for explosives detection canine teams to be deployed across the Nation's surface and maritime transportation networks, including in venues of multiple modes of transportation, as the Secretary considers appropriate. (d) Authorization There are authorized to be appropriated to the Secretary to the extent of appropriations to carry out this section for each of fiscal years 2019 through 2021. 1972. Study on security standards and best practices for passenger transportation systems (a) Security standards and best practices for United States and foreign passenger transportation systems The Comptroller General of the United States shall conduct a study of how the Transportation Security Administration— (1) identifies and compares— (A) United States and foreign passenger transportation security standards; and (B) best practices for protecting passenger transportation systems, including shared terminal facilities, and cyber systems; and (2) disseminates the findings under paragraph (1) to stakeholders. (b) Report Not later than 18 months after the date of enactment of this Act, the Comptroller General shall issue a report that contains— (1) the findings of the study conducted under subsection (a); and (2) any recommendations for improving the relevant processes or procedures. 1973. Amtrak security upgrades (a) Railroad security assistance Section 1513(b) of the Implementing Recommendations of the 9/11 Commission Act of 2007 ( 6 U.S.C. 1163(b) ) is amended— (1) in paragraph (1), by striking the period at the end and inserting , including communications interoperability where appropriate with relevant outside agencies and entities.