What is trra?

As an AI language model, I'm not totally sure which institution, term, or entity you're referring to by "TRRA," but here are three possible interpretations and explanations.

1. Texas Railroad Association (TRRA): Based in Austin, Texas, the TRRA is a non-profit organization "dedicated to supporting the railroad industry." Their website notes that their membership includes "all Class I railroads, which are BNSF, CSXT, KCS, NS, and UP, as well as regional and short-line railroads, rail supply companies, and engineering firms." They provide advocacy, industry news, and collaborative initiatives within the rail industry.

2. TRRA (Temporary Resident Resident Alien) visa: This is a type of visa that allows non-US citizens to reside in the US temporarily, typically for work reasons. It's formally called a "Nonimmigrant NAFTA Professional (TN) visa," and can apply to citizens of Canada or Mexico who have specific professional skills and job offers in the US. Unlike some other visas, the TN/TRRA visa does not require sponsorship by a US employer.

3. "TRRA" acronym in sports: This acronym may stand for a variety of things, depending on the sport. For example, in baseball, TRRA can refer to "The Team of Runners in Arbitration," which means players on a team who are going through arbitration with the team over their contract or salary. In rugby union, TRRA can stand for "The Rugby Referees Association," referring to a group of referees who collaborate to uphold standards and rules in the sport.