[Tagging] Adding values to usage=* key for power transmission

[Rainer Fügenstein]

MR> I do not know why anyone should tag one OSM way both with power=* and
MR> railway=*.

and here I contradict my own oppinion:

In many cities, there's a gas pipeline running under (almost) every
street, providing gas to domestic homes (as do water, sewage ...)

just imagine a city like vienna, drawing one or more man_made=pipeline
ways parallel to nearly every highway=* - a nightmare, editing-wise.

in these cases, it would be better to use the already existing
highway=* way and also tag it as man_made=pipeline. and here we have
the first name=*, ref=* conflict, only to be solved by prefixes.

similar situations where pipelines run underneath bridges to cross a
river (etc).

can't speak for the power guys here, but rather unlikely that
something runs directly underneath/above a high voltage power line ;-)

cu