build a railroad tracks on top of big pile of ballast

[Marco927]

 

Some railroad tracks are built by bringing in large amount of ballast and then tracks are laid on top of the big pile of ballast. What do you call this type of railroad building? What was the cost of constructing this kind of railroad per mile in the 19th century and early 20th century? What materials are used in the piles?

[trainfan22]

That type of railroad building is called an "Embankment".

 

https://en.m.wikipedia.org/wiki/Embankment_(earthworks)#:~:text=A road%2C railway line%2C or,detour to follow a contour.

[bobtehpanda]

Pros and cons of embankments:

• dirt is cheap and we know how it works. To a large extent, a lot of the embankments were created before we had extensive concrete technology
• From a pure materials standpoint, dirt is still cheaper than concrete
• Embankments are wider than an equivalent concrete structure because they need to slope and drain properly. Their profile needs to look like a hill to be stable. This makes them too expensive in places where land costs too much; what are the suburbs today in the 1800s was very empty
• Embankments are more prone to certain kinds of damage over time (like erosion) and don't deal well with certain kinds of disasters (like earthquakes)