CREATE TABLE table_204_882 (id DECIMAL, "number" DECIMAL, "builder" TEXT, "entered service" TEXT, "withdrawn" TEXT, "notes" TEXT)

how many locomotives were still in service after the year 1950 ?
SELECT COUNT(*) FROM table_204_882 WHERE "entered service" <= 1950 AND "withdrawn" >= 1950
SELECT COUNT(*) FROM "table_204_882" WHERE "entered service" <= 1950 AND "withdrawn" >= 1950