Like the TE3s , the DFs were designed to be used in pairs , back to back .
Like the TE3s , the DFs were appear to have spent most of their lives working singly , hardly a problem when there were wyes everywhere to turn steam locomotives .
Like the TE3s , the DFs were designed to be used in pairs , back to back , but appear to have spent most of their lives working singly , hardly a problem when there were wyes everywhere to turn steam locomotives .