Which is why ABS exists. When you lock your wheels up your coefficient of friction tanks and your stopping distance can double or more depending on conditions. ABS unlocks your wheels sometimes so you can at least steer, unlike a skid. If you know how to pump brakes properly a skilled driver can beat ABS handily.
There’s also the fact that couplers have these hard rubber disks that act as springs and shock absorbers (railroading is kind of caveman-like in its solution to things) so when you try to pull a train it might look like you’re moving but you’re just taking the slack out. If you don’t you can bust a coupler from shock loading, so you can’t cheat physics that way (how I move heavy furniture around by myself personally so you would think it applies to trains)
As a result you take the slack out of a train and make the cylinder part of the boiler until:
A) she moves!
B) your wheels slip!
Once it’s moving it’s easy going.
As for why an electric engine can’t keep hauling overloaded it’s because it’s above 100% rating. It can only do that for a short while or things start melting and letting out magic smoke.
A steam locomotive can haul anything it can get moving since it’s lower friction once rolling, and requires less drawbar force.
I see. So the difference is that electric motors can provide a momentary burst of torque which is higher than their sustained capacity. And steam engines can’t do that, if they could, then the same “problem” would arise for them, right?
Yup! Which is why some steam trains had starter gear or “boosters” which was a 3rd piston geared down a lot into a normally unpowered axle. It was only active at low speeds but provided extra starting torque to get things moving
Oh that’s very interesting. I thought starting to move is harder than keeping things in motion
In order of most frictiony to least frictiony
Stiction (stationary object you forced to move)
Rolling
Sliding
Which is why ABS exists. When you lock your wheels up your coefficient of friction tanks and your stopping distance can double or more depending on conditions. ABS unlocks your wheels sometimes so you can at least steer, unlike a skid. If you know how to pump brakes properly a skilled driver can beat ABS handily.
There’s also the fact that couplers have these hard rubber disks that act as springs and shock absorbers (railroading is kind of caveman-like in its solution to things) so when you try to pull a train it might look like you’re moving but you’re just taking the slack out. If you don’t you can bust a coupler from shock loading, so you can’t cheat physics that way (how I move heavy furniture around by myself personally so you would think it applies to trains)
As a result you take the slack out of a train and make the cylinder part of the boiler until:
A) she moves!
B) your wheels slip!
Once it’s moving it’s easy going.
As for why an electric engine can’t keep hauling overloaded it’s because it’s above 100% rating. It can only do that for a short while or things start melting and letting out magic smoke.
A steam locomotive can haul anything it can get moving since it’s lower friction once rolling, and requires less drawbar force.
I see. So the difference is that electric motors can provide a momentary burst of torque which is higher than their sustained capacity. And steam engines can’t do that, if they could, then the same “problem” would arise for them, right?
Yup! Which is why some steam trains had starter gear or “boosters” which was a 3rd piston geared down a lot into a normally unpowered axle. It was only active at low speeds but provided extra starting torque to get things moving