As far as I can tell, there are only two sections that could potentially have something to do with surveying and drawing:
Section 1050.7 - Disorderly conduct
Can't find anything in this section; and
Section 1050.9 - Restricted areas and activities
The only provision I find relevant is this:
(c) Photography, filming or video recording in any facility or conveyance is permitted except that ancillary equipment such as lights, reflectors or tripods may not be used. Members of the press holding valid identification issued by the New York City Police Department are hereby authorized to use necessary ancillary equipment. All photographic activity must be conducted in accordance with the provisions of this Part.
So, if I understood the rules correctly, as long as I do not use flash when I take my photos, and do not create any trouble, or cause any disturbance or interference to the operation of the train system, I should be fine.
This is a project I really want to continue to develop, and the last thing I want is to get into trouble. If you think I missed anything, please drop me a comment, thanks!