CREATE TABLE table_20187 ("Class" TEXT, "Wheel Arrangement" TEXT, "Railway" TEXT, "Number at Doncaster" FLOAT, "Number at Pyewipe" FLOAT, "Number at March" FLOAT)

Name the railway when class is j19
SELECT "Railway" FROM table_20187 WHERE "Class" = 'J19'
SELECT "Railway" FROM "table_20187" WHERE "Class" = 'J19'