Trains vs trucks...

[85_Ranger4x4]

Newer ships are made that way as well, diesel-electric

So the diesels can run at consistent lower RPM after train/ship is up to speed

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.

 

[rusty ol ranger]

Train cars do roll very easy. At my old job we had a 11000lb capacity, dual front wheeled toyota forklift, powered by a 90hp (or 115hp, i cant remember) N/A yota I6 diesel, and it would push 4 or 5 loaded with lumber.

It was grunting hard and would overheat the trans pretty quick if you went very far, but it would do it.

Fun part was getting them stopped by just turning the hand brake, even at 5mph.

One time i almost pushed them out the gate onto the mainline, had to get them fast enough to go thru the yard switch, but not fast enough to go thru the gate, guy turnin the hand brake couldnt get it whoa'ed, i had to haul ass in front of it (that lift did like 20) and let it bump the counterweight, then stand on the lift brakes, that was only 2 or 3 cars and the amount of momentum there was nuts

 

[Truckedup]

I'm no rail road expert but I believe an empty box car can weight about 60,000 pounds...Gross weight for many is 268,000 pounds...

 

[don4331]

There was a Mack in Australia which pulled 112 trailers (1,300tons) for 140m for the record.

Assuming the 268k lbs is correct, that's equivalent to about 10 railroad cars. Coefficient of steel on steel is less than rubber on tarmac, so you could probably pull 20-25 cars.

Single river barge is 1,500 tons and they lash 30+ together for a single tow...

 

[adsm08]

They use smaller tow vehicles to move railcars around the yards, they are basically tractors, even have rubber wheels so they can leave the tracks and move to another track to move other cars where they need to be
They just have added retractable steel wheels, but still use the rubber tires for traction

Norfolk Southern has a mess of rail-service trucks built with that system. Mostly F350s.

The first dealership I worked at was literally right next to the NS yard in Harrisburg, and we would get those things in all the time. We had one lift that could pick them up, and it could only do the front end, rear axle had to stay on the ground. It was too heavy for the lift.

They were DRW trucks with the outer wheel removed. With all the extra gear the rear springs had a negative arch.

 

[85_Ranger4x4]

There was a Mack in Australia which pulled 112 trailers (1,300tons) for 140m for the record.

Assuming the 268k lbs is correct, that's equivalent to about 10 railroad cars. Coefficient of steel on steel is less than rubber on tarmac, so you could probably pull 20-25 cars.

Single river barge is 1,500 tons and they lash 30+ together for a single tow...

It isn't really hard to push stuff around in water though if you are not in a hurry.

 

[adsm08]

It isn't really hard to push stuff around in water though if you are not in a hurry.

Don't you still have to produce enough thrust to overcome the static inertia of whatever you are pushing?

 

[85_Ranger4x4]

Don't you still have to produce enough thrust to overcome the static inertia of whatever you are pushing?

I don't know how it all pencils out, some of those river boats can get 80 semi trucks worth of stuff on one barge and can push 40 barges with 10k hp. I don't know how much hp a truck has, high hundreds maybe a thousand?

So figure they are moving 3200 semi trucks worth of stuff with maybe 10-15x a normal semi truck hp.

 

[rusty ol ranger]

Trucks range from 450-600hp. Average is 450-475 for your tuned down schnider specials, 500-550 is your average owner op truck, 550-600 is the michigan special/heavy haul trucks


EDIT....

Truck vs tugboat...

https://youtu.be/a6HUFm6FKD4

 

[85_Ranger4x4]

Trucks range from 450-600hp. Average is 450-475 for your tuned down schnider specials, 500-550 is your average owner op truck, 550-600 is the michigan special/heavy haul trucks


EDIT....

Truck vs tugboat...

https://youtu.be/a6HUFm6FKD4

Personal experience, in tug of war first guy to slip or spin looses unless the other guy doesn't want him to.

 

[adsm08]

I don't know how it all pencils out, some of those river boats can get 80 semi trucks worth of stuff on one barge and can push 40 barges with 10k hp. I don't know how much hp a truck has, high hundreds maybe a thousand?

So figure they are moving 3200 semi trucks worth of stuff with maybe 10-15x a normal semi truck hp.

Right, and I know that water changed some things, especially some of the friction coefficients, and it may add a multiplier to the thrust numbers, but my basic understanding of the physics, from most of the articles I read about the complexities of interstellar space travel, is that no matter the situation, if you want to move something the thrust you generate has to be at least equal to the mass of the item you are moving.

 

[Truckedup]

I don't know much about calculations but I do know boats are a lot slower than wheeled vehicles with the same HP....A 22 foot boat weighing 4000 pounds with 300 hp is good for maybe 50 MPH or so...And at any speed it takes a lot more throttle opening to keep a boat moving...

 

[adsm08]

I don't know much about calculations but I do know boats are a lot slower than wheeled vehicles with the same HP....A 22 foot boat weighing 4000 pounds with 300 hp is good for maybe 50 MPH or so...And at any speed it takes a lot more throttle opening to keep a boat moving...

Yes, but water does not behave as an entirely Newtonian fluid. As you get up speed the water starts increasing resistance much faster than air does.

 

[Truckedup]

Hell, even a Chevy can pull a heavy load on flat ground


https://www.youtube.com/watch?v=LL4OeiMjvtk

 

[85_Ranger4x4]

Yes, but water does not behave as an entirely Newtonian fluid. As you get up speed the water starts increasing resistance much faster than air does.

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.