4 ms·
> Without the ballast in place, railway lines would simply not be able to cope with the stress from the weight of the trains passing over them, not to mention t
by rhn_mk1 3y ago
> Without the ballast in place, railway lines would simply not be able to cope with the stress from the weight of the trains passing over them, not to mention the impacts of expansion and contraction.
How does this relate to tram lines? They don't seem to have much ballast at all, and they are often just inset into asphalt, so there's no draining, and the asphalt presumably limits expansion and contraction?
- mkl 3y agoTrams are much lighter and have way fewer carriages/cars, so I expect the need is much reduced. The foundation of the road is probably even more sturdy than the ballast, and there are gaps between rail sections for expansion.
- usr1106 3y agoThe speeds you can reach on traditional tracks embedded into streets is much lower. Outside of cities where trams run at higher speed ballast is preferred. Modern tram tracks have a steel-enforced concrete base under the street, similar to ballast-free highspeed tracks.
- snowwrestler 3y agoLong-haul rail lines are engineered to support freight loads, which can be extreme. Local passenger lines have lighter cars that are mostly enclosed air, and commensurately lighter engines as well.