When all three systems came under city ownership in 1940, essentially nothing was done to standardize signage for two decades. Stations on the IRT and BMT still said "Interborough" or "BMT Lines" or sometimes older designations. Services continued to be signed by their traditional methods for each system. IND and post-Second World War ("R-type") equipment used BMT numbers when operating on BMT services. With the introduction of R12 equipment on the IRT in 1948, IRT subway services (except for the 42nd Street Shuttle) began using the route numbers still used today, which had been used internally but not on trains or maps. Astoria Line trains were only signed as 8 for a year, after which the line, which had been shared with the BMT, was converted for BMT operation only (and the Flushing Line carried only IRT trains).