The patents address traction a little bit. The mass would be highly concentrated near the drive unit. So it&#x27;s more of a system for stacking weights on locomotives than it is a system for pushing trains up a hill.<p><a href="http:&#x2F;&#x2F;www.google.com&#x2F;patents&#x2F;US8674541" rel="nofollow">http:&#x2F;&#x2F;www.google.com&#x2F;patents&#x2F;US8674541</a><p><a href="http:&#x2F;&#x2F;www.google.com&#x2F;patents&#x2F;US8593012" rel="nofollow">http:&#x2F;&#x2F;www.google.com&#x2F;patents&#x2F;US8593012</a>