alaskan pipeline
the alaskan pipeline is an engineering marvel. the oil has to be kept hot or it stops flowing. surprisingly, to me at least, it's the friction from pumping the oil through the pipe that keeps it hot. the permafrost under it has to be kept frozen or it will create sinkholes. there are ammonia refrigerators to keep the permafrost frozen. the temperature varies from 50 degrees below to 70 degrees above. the pipeline expands and contracts quite a bit. it's not attached to the support structures. it's free to snake back and forth on them. which i think is kinda funny. alaska's getting warmer. which is worrisome. because many of the clever engineering tricks won't work if it gets too much warmer. but that's okay. if it does get that much warmer the ice will be gone and we can move the oil by tanker ship.