1 The water table forms the top of the zone of saturation, where pore spaces in sediment or rock are completely filled with water. 2  Aquifers are underground areas of sediment or rock that hold groundwater. 3  In steep areas, where groundwater intersects the ground surface, a spring or seep can form.
There's a word for what you're asking for-- onomatopoeia. Many times editors would rather you not use the sounds, but describe it, unless you're writing a PB or even early chapter book. I wrote about a train in one of my short stories. As a train gets closer, it makes a rumbling sound. As it leaves the station, it makes a steadily increasing chugging sound. The whistle sounds like a forlorn call in the night. The brakes hiss and screech when the train slows down to a stop. If you don't have a train nearby to listen to, go online and do a search.
RAILROAD SIGNALS HOME. Whistles and horns played an important part in railroad history as much as any other railroad related device. They provide protection for trains that people can hear, as opposed to most of the other forms of signaling which require someone to SEE the warning or information.