How much can they pull?

[64Warhorse]

The locos that come with the Marias Pass Route X are set up so that they get less traction in rainy weather (which is a real PITA when dragging heavy freight uphill! :hehe: ), but I think there are special scripts involved for that.

 

[TRam__]

in actual fact the contact area between rail and tyre is very little, I can't remember exactly

1 - 2 mm sq.

 

[Vern]

I believe in the US, railroads work on a basis of 2 - 3hp per ton of trailing weight, on heavily graded lines.

In the UK we get away with more, for example the Mendip stone trains will frequently have a single Class 59 loco (3300 hp) hauling trains in excess of 4000 tonnes which is well under 1hp per tonne. However, the Class 59's are specifically geared for this particular work. On the steepest continuous main line gradient in the UK, 1 in 37 Lickey Incline from Bromsgrove to Blackwell 2 miles, the maximum load for a 3300hp Class 66 is 1070 tonnes before a banker is required.

However it all depends on the motive power weight gearing, weather conditions etc. - for example it is not unknown for HST's climbing the Devon banks to slip to a stand or be overpowered in poor rail conditions or if a power car is dead. Despite being some 2200 hp on each power car, they are only 80 tonnes and express geared for 125 MPH so easily get into trouble, on a relatively light 300 tonne load.

 

[TRam__]

The power and the maximum tracktion force are independent. The tracktion force depends on locomotive's weight and quallity of its suspension and its transmission. But, of course, less power decreases the speed.

 

[Racn]

Thanks guys, really informative.

 

[JCitron]

You might find this interesting...
http://en.wikipedia.org/wiki/Slippery_rail

Leaf problems which plague my area from late September through early December.

John

 

[Racn]

Didnt know that a train can wear a flat spot on their steel wheels from braking, but wow , just like rubber tires in Nascar.

 

[64Warhorse]

And apparently, it takes about that long, too ...

 

[Robert2d6]

Didnt know that a train can wear a flat spot on their steel wheels from braking, but wow , just like rubber tires in Nascar.

Or tires in an aircraft if you get too happy with the brakes.

 

[JCitron]

Didnt know that a train can wear a flat spot on their steel wheels from braking, but wow , just like rubber tires in Nascar.

I rode on an Amtrak train from Boston to Philadelphia that had a flat spot on the locomotive. We had changed from diesel to electric at New Haven and the ride was very rough. We ended up swapping locomotives in Stamford, CT, making us about 90 minutes late because we had to wait for another ending to be brought in from somewhere to continue the journey.

John

 

[Racn]

That would be a rough ride, hope they had a biffy on that train, (with all that vibrsation everyones bladder got a workout ), the article read that those wheels arent cheap to replace either.

 

[JCitron]

That would be a rough ride, hope they had a biffy on that train, (with all that vibrsation everyones bladder got a workout ), the article read that those wheels arent cheap to replace either.

It was quite a rough ride. The power kept cutting out too because of poor contact on the wheel. I can imagine the wheel being a costly fix because of the manual labor needed to fix it.

This would be an interesting effect to try to imitate in Trainz. I'm not a content creator or a phyics programmer, so I wonder how this would be implemented.

John

 

[jjanmarine3]

perhaps some guys will find the following interesting.
Recovery teams carry a 'pony bogie' with four small dia wheels with roller bearings on the recovery vehicle which is assembled on the scene ( all the different parts are painted different colors to make assembling easier and fitting properly ) and inserted in the section under a locomotive wheel that has failed due to loose tires , skidded wheels , failed bearings etc . This bogie had an adjustable cradle with wedges which was adjusted to clear the flanges of the failed wheel around corners etc. Water is fed from water bottles onto this emergency bogies wheelflanges to cool it on the way back to the depot or nearest station, sometimes many km's away.
Then one could also 'carry' a failed wheel by inserting spacers under the hornstays , which lifts the failed wheel off the rails and that wheel is then carried by the other wheels because of the even distribution of weight by design of the suspension on locomotives. This 'pony bogie' was also inserted under rolling stock just behind the couplers in the centre to lift one complete failed bogie off the rails.
You might find it interesting to know too that when there is a 'synchronised' wheelslip ( all the wheels slip together - on diesels and electric units ) the wheelslip warning and safety control system cannot pick it up and inexperienced drivers could let the wheels spin so much so that hollows will be worn in the rails under each wheel of a loco . Such spinmarks can be seen on rails often and sometimes they are so deep that the rails have to be repaired . Flat spots on the wheels cause havoc on the tracks in winter, often rails would crack and break in cold temperatures.The recovery crew would then 'escort' the hospital train to it's destination @ 10 mph or so depending on circumstances . Plenty overtime and Sunday time , but it is blood money