Mike,
To the best of my knowledge, Lionel didn't make a UP SD70 non-powered, but check out the following 3 UP non-powered locomotives if you don't mind mixing your motive power:
6-28328: AC6000 dummy
6-28379: DD35A #80 dummy
6-28390: DD35A #79 dummy (with flag scheme)
The non-powered DD35A's are great 'cause they have electro-couplers and operating smoke units... both of which have become all but extinct features on Lionel non-powered locomotives nowadays.
David