Is it permitted to ride in a Shabbat elevator?

Greetings, 

An automatic elevator, which goes up and down without hand contact, and opens and locks at each floor, is permitted by the letter of the law to use on Shabbat, both to go up and to go down. This is especially so in a case of need, such as an elderly person or a sick person, or a woman in labor or a woman with a double stroller, and the like. However, one should be careful not to enter the elevator while the door is closing, since that activates an electrical circuit that causes the elevator to open again. In any case, where it is possible, it is proper to be strict and not descend in an automatic elevator. 

Sources: See Halichot Olam, part 4 (page 158), and Kitzur Shulchan Aruch Yalkut Yosef, part 1 (page 773, section 8). Also see Yabia Omer, part 11 (Orach Chaim, siman 24), and what is cited on this in Piskei Teshuvot (siman 248, ot 2, beginning with the words ועוד). 

With blessing, Hillel Meirs