Table: southern_rail_locomotives
Columns: class
wheel_arrangement
lcdr_number_s
secr_numbers
manufacturer
year_made
quantity_made
quantity_preserved
year_s_withdrawn

Question: Which SECR numbers have a class of b1?
SQL: SELECT "secr_numbers" FROM southern_rail_locomotives WHERE "class" = 'b1'

Question: Which class was made in 1880?
SQL: SELECT "class" FROM southern_rail_locomotives WHERE "year_made" = '1880'