when did each locomotive enter service?
march 1983, august 1983, september 1983, october 1983, december 1983, november 1983, february 1984, april 1984, june 1984, july 1984
what are their serial numbers?
83-1010, 83-1011, 83-1012, 83-1013, 83-1014, 83-1015, 83-1016, 83-1017, 83-1018, 83-1019
which of those serial numbers belongs to the oldest locomotive?
83-1010