> Camera will be problematic, sub tunnel is dusty and moist,=20 If it is anything like the London underground, can you measure the speed of the pressure wave of an approaching train? --=20 Scanned by iCritical. --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .