Trains vs trucks...

[adsm08]

The square vs cube rule still kind of applies. roughly as your speed doubles your drag quadruples.

Like how a 400hp Mustang will do 150mph pretty easy but it takes a 650hp Shelby half a day to break 200mph.

For ships the Iowa class was a slightly more refined South Dakota class with a more efficient hull.

SoDak had 130,000hp and topped out at 27kts. Iowa had 210,000hp and would do 33kts. They were right there at the wall, that is a lot more power on a longer more efficient hull for 6 kts.

Yeah, but Iowa also had an additional 10,000 ton displacement over South Dakota.

 

[85_Ranger4x4]

Yeah, but Iowa also had an additional 10,000 ton displacement over South Dakota.

And 82,000 more hp. Most of the weight was the extra 180' of pointy bow. (length also helps with speed in ships)

 

[rusty ol ranger]

I dont know much about boats, but could some of the top speed issues be related to the fact they dont have different gears? Or atleast the ones ive experenced dont. So you basically are limited by the engines rev range.

Except in a vehicle you have 1,2,3 etc.

 

[planeflyer21]

Since trains are special vehicles on special roads...

How much are the Titan mining dump trucks moving with how much horsepower/torque?

 

[Truckedup]

Since trains are special vehicles on special roads...

How much are the Titan mining dump trucks moving with how much horsepower/torque?

From the Internet, 350 tons with 3300 HP... Diesel over electric..

 

[85_Ranger4x4]

I dont know much about boats, but could some of the top speed issues be related to the fact they dont have different gears? Or atleast the ones ive experenced dont. So you basically are limited by the engines rev range.

Kinda sorta not really.

Steam would kind of be like a hydrostat. If you want more you open the valve(s) up more and you go faster.

The early steamers were direct drive, around WWI they started having gear reduction to keep the engines in their happy place. Now they have geared gas turbines with variable pitch propellers and the newer destroyers are gas turbine over electric and I assume they still have variable pitch screws.

 

[ericbphoto]

Kinda sorta not really.

Steam would kind of be like a hydrostat. If you want more you open the valve(s) up more and you go faster.

The early steamers were direct drive, around WWI they started having gear reduction to keep the engines in their happy place. Now they have geared gas turbines with variable pitch propellers and the newer destroyers are gas turbine over electric and I assume they still have variable pitch screws.

... and some modern steam vessels use steam turbines. Their speed is at least partially limited by the need to prevent turbine blades from flying off. But, in addition, trying to turn the turbines faster takes a lot more steam. So you also have limits due to the boilers' steam producing capacity.

Sent from my SM-G960U using Tapatalk

 

[85_Ranger4x4]

... and some modern steam vessels use steam turbines. Their speed is at least partially limited by the need to prevent turbine blades from flying off. But, in addition, trying to turn the turbines faster takes a lot more steam. So you also have limits due to the boilers' steam producing capacity.

Sent from my SM-G960U using Tapatalk

Steam turbines caught on during WWI, I think the Nevada was the first battleship to have them, her sister Oklahoma had traditional compound engines for a side by side comparison. Everything after had turbines but a few classes had electric motors to actually move the ship (late WWI era)

USS Iowa following Operation Hailstone:

Cdr (Rear Admiral, posthumously) Moriya Setsuji's (former CO of SUZUKAZE) destroyer NOWAKI flees the onslaught. Both American battleships - the fastest in the world - give chase at 32.5 knots. At 35,000 yards, NEW JERSEY and IOWA open fire and straddle NOWAKI with their first salvos. NOWAKI flees into the sun's glare, so at 38,000 yards both battleships fire under radar control. At 22 miles, these are the longest range shots ever fired by American battleships against an enemy vessel. At 39,000 yards, Admiral Spruance orders Cease Fire. NOWAKI escapes and eventually makes her way back to Yokosuka.

That had to be scary on the Nowaki who had a top speed of 35kts... so she was barely outpacing two battleships firing from beyond the horizon.

Allegedly the captain of the Iowa called for more steam, the engineer reported back he had plenty of steam but nowhere to put it as the throttles were wide open.

And the Rodney bypassed her governors during the Bismark chase and actually beat her test speed while carrying parts for a refit in the US while chasing Bismarck.

So there is some wiggle room especially for short periods of time.

USS Iowa during a high speed run in the 1980's, it is hitting the hulls max speed so the stern is getting sucked down as it tries to force its way faster with more brute force.

http://www.navsource.org/archives/01/0161049.jpg

 

[wildbill23c]

WWI/WWII subs were diesel over electric (diesel subs still are), late WWI battleships were steam turbine over electric, the new Zumwalt class destroyers are gas turbine over electric.

Bit off topic, but what about nuclear subs? Are they 100% nuclear or a combination of diesel/nuclear?

Back on topic. I've seen a pickup truck move an empty rail car, but there's no way it would move one loaded....so I'd guess a semi-tractor could probably move a loaded rail car, probably not multiple cars though unless they could find a way to add enough weight over the drive axles of the semi-tractor...that's where the largest problem is, an unloaded semi-tractor doesn't have much in the way of traction, the weight of the trailer over the drive axles of the semi-tractor is what gives it the traction.

 

[85_Ranger4x4]

Bit off topic, but what about nuclear subs? Are they 100% nuclear or a combination of diesel.

Nuke over electric.

Nuclear subs are nuclear so they can go weeks without any kind of surfacing.

Diesel/electric subs are much cheaper and are a little quieter but do not have near the endurance either surfaced or submerged/snorckling that nuclear has.

Basically this day in age if you have a diesel sub it is because you can’t afford a nuke.

 

[ericbphoto]

Nuclear sub is where I got a lot of my first-hand experience. We had 2 Steam turbines coupled to the reduction gear for the prop shaft. We had 2 more steam turbines that turned generators to produce AC electricity. And we had an emergency diesel turning a DC generator to prolong battery life when the reactor shut down for some reason.

Diesel subs aren't just for the poor people, by the way. When on battery power, they are still much quieter than nuke subs. Quiet is very, very good for submarines. It keeps us alive.

Sent from my SM-G960U using Tapatalk

 

[85_Ranger4x4]

Nuclear sub is where I got a lot of my first-hand experience. We had 2 Steam turbines coupled to the reduction gear for the prop shaft. We had 2 more steam turbines that turned generators to produce AC electricity. And we had an emergency diesel turning a DC generator to prolong battery life when the reactor shut down for some reason.

Diesel subs aren't just for the poor people, by the way. When on battery power, they are still much quieter than nuke subs. Quiet is very, very good for submarines. It keeps us alive.

Sent from my SM-G960U using Tapatalk

I forgot they had steam turbines in the mix too. My forte is WWII era.

Diesels are quiet submerged on electric but they are not as stealthy as nuclear. Nuclear can submerge much farther away from the target and not be spotted. Diesels make a lot of noise when charging batteries and even snorkels can be picked up on radar.

I don't think the US has ran a diesel submarine for quite awhile?

 

[wildbill23c]

Nuke over electric.

Nuclear subs are nuclear so they can go weeks without any kind of surfacing.

Diesel/electric subs are much cheaper and are a little quieter but do not have near the endurance either surfaced or submerged/snorckling that nuclear has.

Basically this day in age if you have a diesel sub it is because you can’t afford a nuke.

Ahh ok thank you. I figured a nuclear sub would be extremely quiet.

 

[85_Ranger4x4]

Ahh ok thank you. I figured a nuclear sub would be extremely quiet.

They have cooling pumps making noise that diesel electric doesn’t have. So when the are trying to sneak around the diesel is actually quieter.

But the nuclear can submerge a lot farther away.

 

[Will]

I didn't read all of this, but they have been doing a lot of work on the tracks around us. They have been using dump trucks fitted with rail wheels to pull up to about 6 rail cars full of crushed stone (ballast I think the railroad calls it), so no question a truck can pull some amount of train.

Traction is the important thing. A locomotive weighs 1/2 million pounds.

Torque is often spouted, but means nothing. Work is what you need--torque is a motionless measurement.

https://tractortestlab.unl.edu/

Tractors are rated in drawbar horsepower. See that link above--they don't mention torque. Meaningless.

So with locomotives. A locomotive is about 5-6,000 horsepower. They use electric motors (steam was used for this reason for far longer than it should have been) because you need the torque at zero-rpm, but if they had to they would pull it into motion with electric cable winches and keep it moving with diesel engines.