Audio signal level controlling apparatus; Masts (wireless aerials); Microprocessing apparatus for monitoring; Point-to-point line of sight radio apparatus; Railroad control apparatus for the control of traffic on railways; Railroad signalling apparatus for the control of traffic on railways; Railroad signalling apparatus for the control of traffic on roads; Railway traffic safety apparatus; Railway traffic safety appliances; Railway traffic signalling instruments; Remote controlled apparatus for use with gates; Signalization apparatus for railways; Wireless transmission apparatus; Traffic control apparatus (electronic); Traffic control apparatus (mechanical); Two-way wireless communication systems; Automatic access control systems; Microprocessing apparatus for controlling; Traffic control installations (electronic); Mechanically operated road traffic control signs; Railway traffic control signals