CREATE TABLE table_63001 ("Class" CLOB, "Railway number ( s ) " CLOB, "Quantity" FLOAT, "Year ( s )  of manufacture" CLOB, "Axle arrangement" CLOB)

What is the quantity for railway 263?
SELECT "Quantity" FROM table_63001 WHERE "Railway number(s)" = '263'
SELECT "Quantity" FROM "table_63001" WHERE "Railway number(s)" = '263'