Disabled voters have access to electronic voting machines in a few ways. First is that some machines are lower on tables for wheelchair access. Another way is that election officials can assist in casting votes for disabled citizens. Other times, the disabled voter can bring someone else with them to vote on their behalf.
In any voting place that uses electronic voting machines, they must have at least one voting machines that is accessible to those who are disabled. Obviously these places would be required to provide a way of voting for every citizen regardless of physical ability, or else they would be violating a major law.