390 ITU‐T's Technical Reports and Specifications Figure 1 – Solid waste collection [Source: Nilesh Puery, b‐2] Collective antennas for wireless systems [b‐28] Ducted transport (e.g. pneumatic tubes [b‐28] or automatic railway [b‐10]) NOTE – Usually subway signalling systems (e.g., Leaky coaxial cable or rail transit wireless communication system) are not taken into consideration as these are most likely to be an independent underground service. [b‐26] classifies the underground pipelines into 8 categories according to the functions, i.e. water supply, drainage, gas, heat, electricity, telecommunication, industry and other pipelines (Figure 2).