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> ARES wants to lay a nearly 5.5 mile track up an 8 degree slope, gaining about 2,000 feet top to bottom. An 8 degree gradient is super steep. Regular trains (

by chiph 11y ago

> ARES wants to lay a nearly 5.5 mile track up an 8 degree slope, gaining about 2,000 feet top to bottom. An 8 degree gradient is super steep. Regular trains (not funiculars) start to have traction problems around 2-2.5%

maxerickson 11y ago
The patents address traction a little bit. The mass would be highly concentrated near the drive unit. So it's more of a system for stacking weights on locomotives than it is a system for pushing trains up a hill. http://www.google.com/patents/US8674541 http://www.google.com/patents/US8674541 http://www.google.com/patents/US8593012 http://www.google.com/patents/US8593012
TylerE 11y ago
It is super steep, but it's not unprecedented. Several Swiss railways have extended 7% grades and have been operating for over a century. https://en.wikipedia.org/wiki/Bernina_railway https://en.wikipedia.org/wiki/Bernina_railway for instance The problem with steep railway lines is generally BRAKING, not climbing. Norfolk Southern ran freight up and down the Saluda grade in NC for over 100 years, and that's at nearly 5%.
takno 11y ago
Generally speaking in the UK this was addressed by adding banking engines (the steepest sustained mainline gradient in the UK is 1:37 and this isn't enough to cause problems for modern trains). This suggests the problem is an economic one with a mix of banks and flat running. If you are only running a gradient you can provide more traction power and have done
- chiph 11y ago
  The problem is adhesion (lack of). Modern traction control systems (anti-slip) help quite a bit, but eventually you'll exceed what the steel-on-steel mating surface can provide in terms of grip. Traditionally, you overcome this by using a heavier locomotive - which is one reason why the Union Pacific Big Boy was 1.2 million pounds (544,000 kg). It sounds like they're addressing this by making pretty much every car it's own locomotive. https://www.youtube.com/watch?v=0cd5Vcbi1gg https://www.youtube.com/watch?v=0cd5Vcbi1gg

by chiph 11y ago

maxerickson 11y ago

The patents address traction a little bit. The mass would be highly concentrated near the drive unit. So it's more of a system for stacking weights on locomotives than it is a system for pushing trains up a hill. http://www.google.com/patents/US8674541 http://www.google.com/patents/US8674541 http://www.google.com/patents/US8593012 http://www.google.com/patents/US8593012

TylerE 11y ago

It is super steep, but it's not unprecedented. Several Swiss railways have extended 7% grades and have been operating for over a century. https://en.wikipedia.org/wiki/Bernina_railway https://en.wikipedia.org/wiki/Bernina_railway for instance The problem with steep railway lines is generally BRAKING, not climbing. Norfolk Southern ran freight up and down the Saluda grade in NC for over 100 years, and that's at nearly 5%.

takno 11y ago

Generally speaking in the UK this was addressed by adding banking engines (the steepest sustained mainline gradient in the UK is 1:37 and this isn't enough to cause problems for modern trains). This suggests the problem is an economic one with a mix of banks and flat running. If you are only running a gradient you can provide more traction power and have done

chiph 11y ago
The problem is adhesion (lack of). Modern traction control systems (anti-slip) help quite a bit, but eventually you'll exceed what the steel-on-steel mating surface can provide in terms of grip. Traditionally, you overcome this by using a heavier locomotive - which is one reason why the Union Pacific Big Boy was 1.2 million pounds (544,000 kg). It sounds like they're addressing this by making pretty much every car it's own locomotive. https://www.youtube.com/watch?v=0cd5Vcbi1gg https://www.youtube.com/watch?v=0cd5Vcbi1gg