Table: southern_rail_locomotives_2
Columns: class
wheel_arrangement
lcdr_number_s
secr_numbers
manufacturer
year_made
quantity_made
quantity_preserved
year_s_withdrawn

Question: What was the SECR number of the item made in 1861?
SQL: SELECT "secr_numbers" FROM southern_rail_locomotives_2 WHERE "year_made" = '1861'