Back in the 1960s the city gas works was pushing gas air-conditioning for homes. It was a big marketing campaign. If someone got such a unit, the gas works would send out cards to the neighbors inviting them to come and check it out.
IIRC, in the early 1960s the city converted from manufactured gas (processing coal to create gas) to buying "natural gas". This was because pipelines were built between the oil wells and the consuming cities and collect gas that was otherwise just thrown away.
Although cities had gas works for a great many years, gas was originally used for lighting. Coal was used for heating. In later years gas was used for cooking, hot water, heating, and clothes drying, all because it was cheaper than electricity for those purposes. In those days, one advantage of living in the city was that utility expenses were cheaper -- using gas was cheaper than electricity to run the household. Further, utilities charged city residents a lower rate since the higher housing density was cheaper to serve.
In the 1970s this all changed with the energy crisis. I believe the domestic gas sources ran out and now gas had to be imported from the Middle East along with oil, greatly increasing its cost. Indeed, there were shortages and new housing construction had to use all-electric instead of gas.
On railroads, steam was used for air conditioning. There was an explanation on the railroad newsgroup of how this worked. Steam had the advantage of being freely available as excess from the locomotive boiler.
After the railroads diselized, the diesel locomotives had to contain a water boiler for passenger trains to provide steam for a/c and heat. This continued into the Amtrak era. Amtrak converted all trains to all-electric, eliminating the steam lines which were a problem to maintain.
Someone mentioned Philadelphia's central steam for heating. This was once supplied by the Philaadelphia Electric company in a "steam loop" that circulated throughout center city. Buildings purchased steam instead of maintaining their own boilers. I believe industrial processes could even use that steam. The loop still exists although it was sold off. The steam generators for the loop may no longer be from the electric power plant; Philadelphia Electric has closed down a lot of old power plants. One beautiful old building is being converted into condos. Anyway, the steam loop has had varying fortunes over the years, becoming less popular, but then gaining in popularity again. I believe other cities have similar utility service.
Someone mentioned Bell using jet engines for central office power backup. I'm kind of surprised at this. The electric companies use them for summer supplements. They are very expensive to run, but can get up to speed very quickly. I believe the phone companies use more conventional diesel engines to power generators. If there is a power failure, central office battery has enough capacity to keep things going for a while, more than enough time to power up a diesel engine. (The jet engine has the advtg of being smaller.)
[TELECOM Digest Editor's Note: They did this same thing in parts of downtown Chicago. The boiler in the basement of the Commonwealth Edison (corporate HQ at that time) Building provided steam to many buildings in the area. It was at Clark and Adams Street, right across the street from the old federal court house (for history buffs the very nice, elegant older building with the rotunda and several levels built up under the dome; they tore it down in 1963 when they build the _new_ Federal Plaza on the same spot along with the new post office. When Edison HQ was across the street, they supplied steam for at least five or six buildings along there on Clark Street. PAT]