Wagons - to carry 10.0.0 - tare 6.4.0 - what does it all mean ?

[Guy Rixon]

On 16/12/2020 at 06:57, Gareth 73 said:

I still think its mad that what ever common model railway scale we deal with its Xmm to the foot. But then 2mm to the foot or 4mm to the foot makes some sense when it comes to 9, 6 and 3 inches but 3.5 and 7mm to the foot??

Inches are fine as a tool for modelling railway vehicles specified in imperial measure, but feet less so; there are vastly more dimensions given in inches than in feet on a wagon GA. Mixed feet and inches is unhelpful when computers are involved.  

 

I'm currently finishing CAD for a wagon chassis and my OpenSCAD code is full of macros like middle_bearer_thickness=inches(4.5) and solebar_height=inches(10.67). When it comes to the longer lengths I put wheelbase=inches((9*12) + 9) and similar.

[sulzer27jd]

The first recorded use of painted tare weights was on the Dundee & Newtyle Railway which opened in 1831. On the way to unloading the wagons passed a weigh bridge which gave a reading in the nearby office and the painted tare weight allowed the clerks to note this from within their office and calculate the load. 

 

John

[62613]

14 hours ago, jim.snowdon said:

Which is why on engineering drawings all dimensions are sometimes quoted in millimetres, even though numerically they may run to six digits. No decimal point is required, anything finer than 1mm being lost in the tolerances.

 

Jim

On the top of the sheet: Unless Otherwise Stated, all Dimensions in Millimetres. Having said that,one draffy I know was bollocked by the D.O. supervisor for drawing a piping isometric to the nearest millimetre; the nearest 5mm was close enough!

Edited December 17, 2020 by 62613

[doilum]

3 hours ago, Compound2632 said:

 

Gnats know no borders.

 

Whereas midges, in my experience, are fervent Scots Gnats.

Huge things with a bloody great Merlin engine under each wing........

[62613]

4 hours ago, LMS2968 said:

Are gnat's whiskers imperial or metric?

About the same as a smidgin, no?

 

[doilum]

4 hours ago, Compound2632 said:

BTW I don't buy the suggestion that significant fluctuations in tare weight could be due to water absorption. An increase of 1 qtr would require the absorption of nearly 3 gal.

If the wagon floor has an area of approximately 11 sq metres, 1 mm of rain = 11 litres of water = almost 3 gallons !!!! OK, most would run off but having had the joy of humping wooden joists that have sat in the merchant's yard through a wet month, the difference in weight is not to be scoffed at.

[Compound2632]

1 hour ago, 62613 said:

About the same as a smidgin, no?

 

I don't think so. A smidgin is, I think, larger. Also, I feel sure it's a unit of volume - "Oh go on then, just a smidgin more."

[hmrspaul]

2 hours ago, doilum said:

If the wagon floor has an area of approximately 11 sq metres, 1 mm of rain = 11 litres of water = almost 3 gallons !!!! OK, most would run off but having had the joy of humping wooden joists that have sat in the merchant's yard through a wet month, the difference in weight is not to be scoffed at.

It has always surprised me how much variance there is in tare weights between wagons of supposedly similar manufacture and how much they can differ from the nominal tares given on wagon diagrams. It is more understandable on wagons which have been in traffic for a few years and had a few bits knocked off/rusted off. 

 

And perhaps it is worth remarking that a lot of official photos omit the tare because the photos are taken, for publicity purposes, in the works and before the final operation - the weighing of the wagon for the tare. 

 

I am also interested that many recently built wagons have identical tares - they appear pre-printed on the vinyl for the number area. Doesn't accurate taring matter anymore - perhaps the real tare is regularly entered on to TOPS before loading? 

 

Paul

[billbedford]

The other side of this is to ask how much water 10 tons of coal could hold. 

[Compound2632]

45 minutes ago, billbedford said:

The other side of this is to ask how much water 10 tons of coal could hold. 

 

"Interesting / thought provoking."

[rodent279]

1 hour ago, billbedford said:

The other side of this is to ask how much water 10 tons of coal could hold. 

Well, if it's been raining heavily, and the wagon left the colliery dry, by the time it got to destination, it might be easily a few kg heavier.

[LMS2968]

2 hours ago, billbedford said:

The other side of this is to ask how much water 10 tons of coal could hold. 

Much depends on the 'coal'. Large lumps would not absorb much, but a wagon full of slack could have done. Much would depend on how long it had been exposed to the moisture; a light shower wouldn't make a lot of difference but prolonged exposure in a wet atmosphere would. It wasn't likely to happen to the slack once in the wagon; more likely it would go into it in that condition.

[Dungrange]

So is the gross laden weight of a 10 ton open = 10 tons plus the tare weight?

[Phil Bullock]

Allegedly a scrapper bid for and won a load of 16 ton mineral wagons …. Not a happy chappy when he only got the tare weight of scrap!

[Compound2632]

21 minutes ago, Dungrange said:

So is the gross laden weight of a 10 ton open = 10 tons plus the tare weight?

 

Yes, though perhaps one should say, that would be the maximum gross laden weight, being the maximum load the journals were designed to bear. For many traffics, including coal, the volume of the wagon was often insufficient to accommodate that maximum load. It was generally only stone and stone products and brick where loading an ordinary open to capacity would exceed the maximum by weight; something the loaders would have been well aware of.

[TheQ]

On 17/12/2020 at 14:16, doilum said:

Huge things with a bloody great Merlin engine under each wing........

I thought gnats had Bristol Siddeley Orpheus inside.

[LMS2968]

This was particularly so with vans, which might be labelled as 10T but usually carry about three. That then left an issue od distributing the weight evenly across the floor so that one wheel wasn't heavily loaded while its diagonally opposite number was very light and likely to derailment.

 

[Michael Hodgson]

1 hour ago, LMS2968 said:

This was particularly so with vans, which might be labelled as 10T but usually carry about three. That then left an issue od distributing the weight evenly across the floor so that one wheel wasn't heavily loaded while its diagonally opposite number was very light and likely to derailment.

 

How often did the goods porters worry about weight distribution when loading vans and ordinary open wagons or (even though some parcels vans bore legends about weight being evenly distributed) ?

[Compound2632]

40 minutes ago, Michael Hodgson said:

How often did the goods porters worry about weight distribution when loading vans and ordinary open wagons or (even though some parcels vans bore legends about weight being evenly distributed) ?

 

Presumably it was part and parcel of their job.

[The Stationmaster]

2 hours ago, LMS2968 said:

This was particularly so with vans, which might be labelled as 10T but usually carry about three. That then left an issue od distributing the weight evenly across the floor so that one wheel wasn't heavily loaded while its diagonally opposite number was very light and likely to derailment.

 

Worst (in one resect) load I ever saw in a Vanfit was a single roll of lino - loaded diagonally because that was the only way it would fit.

 

49 minutes ago, Michael Hodgson said:

How often did the goods porters worry about weight distribution when loading vans and ordinary open wagons or (even though some parcels vans bore legends about weight being evenly distributed) ?

The way some vans were loaded, particularly parvans (parcels vans). I reckon the principal objective of those who loaded them was to get in as much as possible wherever they could fit it.  

 

An unforgettable feature of my final year at school was CCF Camp in Mid Wales where I was a member of the advance party (who set up the camp) and the rearguard (who dismantled it).  My job for the latter was loading and arranging the 'military stores' for return to an Army depot into a couple of Vanfits in Machynlleth goods yard - I did all the lighter stuff that could be handled by one person.  Balanced on top of everything else in the middleoft one van, opposite the doors, were all the 'bog buckets' so i was no doubt roundly cursed when the vans were unloaded.  But we did put teh really heavy stuff in first.

[Steamport Southport]

Wasn't that the issue with the Palvans?

 

You were supposed to fill the van by both sides, but unscrupulous loaders just loaded by the doors from one side. So the load was only at one end. Which caused poor riding and derailments.

 

https://paulbartlett.zenfolio.com/brpalvan

 

 

 

Jason

[Jeremy Cumberland]

I've run some engineering trains on narrow gauge lines where we've been very concerned about "evenly distributed" (or as best as could be managed), but most van loads were fairly light and were unlikely to unload a wheel to a dangerous degree. A 12-ton van might have a tare weight of 6 or 7 tons, so you'd probably need something like 3 or 4 tons all in one corner to give rise to a potentially dangerous situation, which is difficult to imagine happening with parcel loads.

 

 

 

[The Stationmaster]

21 minutes ago, Jeremy Cumberland said:

I've run some engineering trains on narrow gauge lines where we've been very concerned about "evenly distributed" (or as best as could be managed), but most van loads were fairly light and were unlikely to unload a wheel to a dangerous degree. A 12-ton van might have a tare weight of 6 or 7 tons, so you'd probably need something like 3 or 4 tons all in one corner to give rise to a potentially dangerous situation, which is difficult to imagine happening with parcel loads.

 

 

 

But conversely most of the vehicles involved in the 'fast freight' spate of derailments in the 1960s seem to have been Vanfits.  The spate of derailments involving mineral type wagons - particularly on stone trains - came later and was quickly traced ti uneven loading as one of the principal factors in the causes of derailment.  Hence the introduction of wheel loading monitoring equipment in addition yo hot box detectors on the B&H route.  

 

Incidentally hot boxes on certain heavily loaded 4 wheel  vehicles. could also be a by-product of uneven loading  although often in conjunction with other factors

[Fat Controller]

5 hours ago, Phil Bullock said:

Allegedly a scrapper bid for and won a load of 16 ton mineral wagons …. Not a happy chappy when he only got the tare weight of scrap!

Don't waste too much sympathy on the scrappy; he'd have  managed to sell the load at least twice. I spent Summer 1974 working at a BSC foundry. where part of my daily duties was checking weighbridge tickets for scrap delivered. against scrap consumed and stock on the ground. We rapidly realised that there were flat spaces where there should have bea]s. The lorry delivering the scrap would go to the slag heap, where a digger driver would put a thin layer of slag on top of the scrap load. He would drive out, receiving a chit for the amount of slag removed. At the yard, the lorry would tip the trailer, where the scrap would be separated, using an electro-magnet, then reloaded and taken back to BSC.  They could have carried on for ages, but. as so often, greed and carelessness crept in; ( though not before they'd made off with a lot of scrap (and consequently charged for removing tonnes of slag which had never moved)

[rogerzilla]

On 17/12/2020 at 15:55, Compound2632 said:

 

I don't think so. A smidgin is, I think, larger. Also, I feel sure it's a unit of volume - "Oh go on then, just a smidgin more."

There's an amusing passage in Lothar-Günther Buchheim's novel "Das Boot" where the very bored U-boat crew start measuring everything in "jets": nautical distances, cups of  coffee, absolutely everything.  Somehow it works.

 

Edited November 7, 2023 by rogerzilla