3 ms·
There is another kind of tyranny equation - the steam locomotive going up an incline. Essentially the problem is the power output of the engine is locked into
by tus666 4y ago
There is another kind of tyranny equation - the steam locomotive going up an incline.
Essentially the problem is the power output of the engine is locked into step with the speed of the wheels - the slower you go, less pushes of the pistons, less power.
So as a steam train starts up an incline, it will start to decelerate, causing it to produce less power, causing it to slow even further and so on. A true vicious cycle.
This was one of many benefits of diesel-electric locomotives - the engine speed (hence power) was decoupled from the train speed.
- jeeeb 4y agoICEs have the same problem though. If they don’t rotate fast enough they stall. For ICEs we solve the problem with gear boxes. Couldn’t the same solution have been used for steam engines?
- tus666 4y agoThey did exist but were not common: https://en.wikipedia.org/wiki/Geared_steam_locomotive https://en.wikipedia.org/wiki/Geared_steam_locomotive
- emtel 4y agoI don’t think that explanation is correct. The torque curve of a steam engine peaks at 0rpm and slopes down from there. The engine is simply decelerating to the point where it’s torque is balanced with the force of gravity on the incline.
- tus666 4y agoIt has no choice but to decelerate, as the train itself will decelerate up an incline (without increasing power), and they are coupled. And yes the torque balance is why steam trains could climb gentle gradients at all. However the loss of power due to fewer piston pushes means that the peak 0rpm is reached very quickly. Diesel electric locos can literally increase RPM and power as they start to climb the gradient, with no connection between the slowing train speed and engine power.