Acronym Soup: BRB?

Questions

The last day of public operation of the Liverpool Overhead Railway was December the 30th of which year?

As what is the tree with the botanical name 'Betula' better known?

Which South American country has borders with only Colombia and Peru?

Which female vocalist had a number one U.K. hit in 1955 with Softly, Softly?

Which U.S. biologist has published collections of essays entitled Bully for Brontosaurus and Dinosaur in a Haystack?