Wright writes.....

[robertcwp]

A full-size 9F double-header: 

92125_92071_nr Long Preston 5-8-67 by Robert Carroll, on Flickr

 

[Tony Wright]

2 hours ago, Lecorbusier said:

what would have been the number of wagons on a typical long goods or mineral train .... for mineral would it have differed between full and empties?

Thanks to those who've answered your question, Tim,

 

On Little Bytham, the maximum number of wagons in any one train - short-wheelbase, empties - is 50 plus a 'van. The fulls are restricted to a maximum of 45 plus a 'van. 

 

These have nothing to do with the haulage limit of the locos, just the length of the fiddle yard sidings. Visually, I think that's enough.

 

The 105 number moved today (several of which were kit-built in white metal and several others which were bogie wagons/vans) was not the limit that the Big Boy, nor the DJH A1 or DJH 9F I also used, could pull, but the train became unstable on the end curves when more were added. Who knows? At least 125 (and more?) would have been feasible, given a greater end radius than three feet. Both the A1 and the 9F needed to back up at least 20 wagons to get the train on the go (prototypical?), but the 4-8-8-4 was more sure-footed on starting - as expected? 

 

Regards,

 

Tony. 

 

 

[uax6]

13 minutes ago, APOLLO said:

On my American O gauge layout the longest train I run is 24 freight cars - which is over 24 feet long and snakes round the level low level track. The other line has gradients up to the higher level, two Atlas twin motored diesels will pull the load, but I have had a couple of Weaver plastic couplings pull their knuckles. Metal Kadees are OK. Lights dim in the shed when this train runs !! - 18 cars is therefore the limit for this line.

 

 

18 car train on the low level line, caboose on left, locos on right. Some cars screech and groan on the sharp curves, just like the real thing.

 

Brit15

 

Nice use of ex-Key and Lamp units there!

 

Andy G

[Tony Wright]

17 minutes ago, t-b-g said:

 

Indeed it was there and they were yours. We kept hanging more on the back until we ran out of wagons and track.

 

It was my little 0-6-0 LMS Diesel shunter that managed to match the two big locos! I never have found its top haulage limit. I think I had 135 behind it round Retford one time.

 

Happy days!

I think my son Tom's twin-motor (O Gauge motors) DP1 took over 50 kit-built cars round Retford on one occasion, Tony.

 

Adding more caused the leading cars to 'implode' on the end curves.

 

You'll have to borrow it one day and give it a maximum test!

 

Regards,

 

Tony. 

[Buhar]

As Clive has indicated in his examples, the nature of the line the train was to run on was the biggest factor in mineral train length.  The length of refuge sidings or loops, the presence of gradients and sharp curves, the capacity of the despatching/receiving yards and the intensity of traffic on the line.  Freight locos, even in the late Victorian period, could haul prodigious loads, if slowly.  For example the train the smash at Gretna in 1901 involved a tiny old Caley 2-4-0 that had hauled 44 wagons from Glasgow over Beattock (albeit southbound).  Later the Caley had decided not to use their 0-8-0s on this route because they were too slow and held up the passenger traffic.

 

If there were severe gradients pinning down the required number of brakes would cause a delay on a long train, plus if there were a dip (such as found on the Stranraer line) part of the train would now be ascending when stopped to take the brakes off following the descent.  Snatches and snapped couplings were a serious risk and the brake van had to be capable of holding the train if it were to be divided.  IIRC the Stranraer line had a limit of 35 wagons.

 

However, the LYR just before WWI had a policy of "long trains" of over a 100 wagons in hilly Central Lancashire, including the route over the notorious Copy Pit incline.  That was hauled by an 0-8-0 with two other engines banking (more may have been added to deal with Copy Pit).  These ran at night and were extremely slow but the LYR seem to have been wedded to the view that they were efficient.

 

In reality a 3F or 4F could probably manage any load required of it on most lines (probably up at about 50 wagons).  The GWR from South Wales to London, the GNR Main Line and the MR Toton to Brent were exceptions where I believe the infrastructure was improved to provide paths for longer trains than would have been found on most of our railways.

 

Alan

 

 

[APOLLO]

4 minutes ago, uax6 said:

 

Nice use of ex-Key and Lamp units there!

 

Andy G

 

Yes, lucky to have those, and they have been used on several layouts over the years. The two small ones on the right were ex home office police control centre my mate rescued them from the skip during refurbishment. The big one (along with two others on my OO layout) were bought the lot for a fiver back in 1986 from the aptly named "Computer Junk Shop" in Widnes - what a shop that was back then - a veritable Aladdin's cave !!

 

Brit15

[uax6]

The Lanky's long trains were probably helped by the fact that they were seriously pursuing the fitting of continuous brakes to their freight stock, so I wonder if these trains were actually at least partially fitted?

 

Andy G 

[uax6]

Just now, APOLLO said:

 

Yes, lucky to have those, and they have been used on several layouts over the years. The two small ones on the right were ex home office police control centre my mate rescued them from the skip during refurbishment. The big one (along with two others on my OO layout) were bought the lot for a fiver back in 1986 from the aptly named "Computer Junk Shop" in Widnes - what a shop that was back then - a veritable Aladdin's cave !!

 

Brit15

 

Still not that difficult to get hold of! I have a few secreted away for use with my Strowger telephone exchange, but at some point I may have to get rid of them....

 

Andy G

[PMP]

6 hours ago, Neil said:

 

I'm a firm believer that less is indeed more when it comes to layout design but I recognise that it's difficult to discipline oneself to pare away track from an original concept. 

 

The problem wasn’t the track plan, that stayed as was, it was the scenic element, the original concept was based on a theoretical location in central London. As I got further into the build the implausibility and therefore lack of belief of the facility vs location, made it for me unworkable. It looked fine on paper and initial mock up, but soon dawned that it would never have occurred, so I couldn’t ‘believe’ in the project so I changed it, and it subsequently worked better.

[Buhar]

5 minutes ago, uax6 said:

The Lanky's long trains were probably helped by the fact that they were seriously pursuing the fitting of continuous brakes to their freight stock, so I wonder if these trains were actually at least partially fitted?

 

Andy G 

Hi Andy,

Not according to the report of an accident in 1912.  I think minerals were a bit down the list for fitting, the LY had plenty of other wagon types they wanted in faster trains, especially from the docks in Hull and Liverpool (fish, butter, bananas).

 

Alan

[PMP]

10 hours ago, Lecorbusier said:

Difficult though it may be to discipline oneself but, given a situation of limited space, arguably it is the space that should dictate the design/subject. 

 

The space was known, and the track plan designed to fit that space, no changes were required. It was the original scenic element that ‘failed’, once that was sorted the layout was easier to complete, and subsequently has been well received.

Edited August 21, 2019 by PMP
Add pics

[Lecorbusier]

That really reminds me of one of the layouts on the Right Track DVD ?

[Clive Mortimore]

51 minutes ago, Tony Wright said:

Thanks to those who've answered your question, Tim,

 

On Little Bytham, the maximum number of wagons in any one train - short-wheelbase, empties - is 50 plus a 'van. The fulls are restricted to a maximum of 45 plus a 'van. 

 

These have nothing to do with the haulage limit of the locos, just the length of the fiddle yard sidings. Visually, I think that's enough.

 

The 105 number moved today (several of which were kit-built in white metal and several others which were bogie wagons/vans) was not the limit that the Big Boy, nor the DJH A1 or DJH 9F I also used, could pull, but the train became unstable on the end curves when more were added. Who knows? At least 125 (and more?) would have been feasible, given a greater end radius than three feet. Both the A1 and the 9F needed to back up at least 20 wagons to get the train on the go (prototypical?), but the 4-8-8-4 was more sure-footed on starting - as expected? 

 

Regards,

 

Tony. 

 

 

Hello Tony and all

 

I only have a 1967 Freight Train Loads Book for the southern end of the ECML, sadly not one that covers the steam period. I would like to have one or even just view one to see what the differences between the two types of haulage is. If anyone has a copy I could look at or if possible scan some sections that would be great.

 

It would be nice to be able to advise Tony on the loads behind his locos on Little Bytham and Gilbert on Peterborough North.

 

The different classes of train also effect the number of wagons that could be hauled, again just looking at a Brush type 2 on the London to Doncaster, a class 4 (fully fitted express freight, and able to run at 55 mph) was 43 basic wagon units, a class 7* (express freight with a fitted head, running at 40 mph) was 86 basic wagon units as far as Highdyke, from there on wards 94. With a class 7* train the number of fitted wagons with operative brakes coupled to the locomotive was proportional to the load, so a maximum of 86 basic wagon units required at least 7 fitted wagons, 94 basic wagon units needed 9. A Class 7* train could be loaded with more wagons than a class 8 because it had greater stopping power.

 

I say I don't have a Freight Train Loads Book for the steam period on the ECML. I do have a few for the Midland mainline that cover both steam and diesel loadings. You would think it would be a simple ratio of x to y where x is a class of steam loco and y is a diesel. The ratio of wagons between the two can vary from line to line ( or even sections of line) owing to the way the different locos can haul up grades and stop the train running away down hill. Diesels usually haul less unfitted wagons because their braking power was not as good, give them a brake tender and they out pull a steam loco on unfitted freights. 

[Barry Ten]

Enough wagons for you?

 

 

[PMP]

5 minutes ago, Lecorbusier said:

That really reminds me of one of the layouts on the Right Track DVD ?

 

It is indeed the layout I built for, and used for discussion points through the course of that video. Myself and Paul Lunn used the same footprint and track plan to show how that space could be adapted for different designs, as well as using Albion Yard and Bawdsey as practical examples.

[t-b-g]

1 hour ago, Tony Wright said:

I think my son Tom's twin-motor (O Gauge motors) DP1 took over 50 kit-built cars round Retford on one occasion, Tony.

 

Adding more caused the leading cars to 'implode' on the end curves.

 

You'll have to borrow it one day and give it a maximum test!

 

Regards,

 

Tony. 

 

I may be a bit sad to even think about such things but I have often wondered what causes a train to pull off the rails on a curve. I have seen videos of model trains wrapped several times around a very small radius spiral where the whole thing stays on the rails, so why should trains pull off on the inside of a relatively large radius well laid curve like Retford?

 

The science says that it should stay on the rails as the forces are acting in an almost straight line along the train, from one vehicle to the next via the coupling. I wonder if it is the couplings not being at exactly the same height, so when there is a very strong pull on a wagon with a slightly low coupling, the wagon is lifted slightly, enough to cause a wheel to ride up the inside rail.

 

The ones that I saw on the video on the spiral were American and probably had Kadees, which have no element of pull up or down if they are correctly set up. The couplings we used on Tickhill (home made Spratt & Winkle type) didn't pull anything up or down either as all the bars were set at the same height with a gauge.

 

I may have been there that day that Tom's  DP1 went round Retford with that load. I certainly saw it running on the layout at least once with a big load. I think Roy was hoping that it would end up on there permanently when it was finished. It was very impressive!

 

[AndyID]

3 hours ago, t-b-g said:

The science says that it should stay on the rails as the forces are acting in an almost straight line along the train, from one vehicle to the next via the coupling.

 

Hi Tony,

 

Mainly because of friction in the train's wheel bearings the forces in the couplings closer to the locomotive are much greater than they are near the end of the train. Add enough vehicles and at some point the train will "straighten out".

 

The spiral example above is a bit of a cheat. It's not really one "train"*. If all the locos were put at the front the freight cars would derail.

 

*Real trains in the US take advantage of that.

 

Cheers,

Andy

[pH]

4 hours ago, t-b-g said:

 

I may be a bit sad to even think about such things but I have often wondered what causes a train to pull off the rails on a curve. I have seen videos of model trains wrapped several times around a very small radius spiral where the whole thing stays on the rails, so why should trains pull off on the inside of a relatively large radius well laid curve like Retford?

 

The science says that it should stay on the rails as the forces are acting in an almost straight line along the train, from one vehicle to the next via the coupling. I wonder if it is the couplings not being at exactly the same height, so when there is a very strong pull on a wagon with a slightly low coupling, the wagon is lifted slightly, enough to cause a wheel to ride up the inside rail.

 

The ones that I saw on the video on the spiral were American and probably had Kadees, which have no element of pull up or down if they are correctly set up. The couplings we used on Tickhill (home made Spratt & Winkle type) didn't pull anything up or down either as all the bars were set at the same height with a gauge.

 

I may have been there that day that Tom's  DP1 went round Retford with that load. I certainly saw it running on the layout at least once with a big load. I think Roy was hoping that it would end up on there permanently when it was finished. It was very impressive!

 

 

Here's an accident investigation report from the Transportation Safety Board of Canada on a Canadian National train that 'stringlined'. The circumstances were a bit unusual, but there's a discussion of the forces that caused it to come off.

 

(Edit - warning, it's a pdf, in case you're not happy about downloading.)

 

https://www.google.com/url?sa=t&source=web&rct=j&url=http://www.bst-tsb.gc.ca/eng/rapports-reports/rail/2005/r05v0141/r05v0141.pdf&ved=2ahUKEwi2iMyasZXkAhVWtZ4KHeR0DvMQFjAIegQICBAB&usg=AOvVaw3xmKSCBeV3jft7gYH1-Mev

 

One of my sons worked for a company that did geotechnical work for CN in BC. When CN took over the BCR line, on which this derailment happened, they wanted the characteristics of the line entered in their databases in their own terms. My son got to travel the BCR line from North Vancouver to Chetwynd on foot and by speeder, doing this recording. Before they started, they got a detailed safety talk. It included instructions on what to do as trains passed them on curves. If the train was going uphill, they should stand on the outside of the curve; if the train was going downhill, they should stand to the inside of the curve.

Edited August 22, 2019 by pH

[Compound2632]

6 hours ago, pH said:

 

If the train was going uphill, they should stand on the outside of the curve; if the train was going downhill, they should stand to the inside of the curve.

 

Makes perfect sense but doesn't inspire confidence!

[t-b-g]

I can accept all that and agree that is reasonable but....

 

So why didn't my 115 wagon train, round tight curves, pull off when it went right round a circuit with tight curves? Were my wheels somehow having less friction than others. Many of the wagons were travelling in a totally opposite direction. The train was heavy and needed a lot of tractive effort to pull it, so as soon as the loco went from the curve to the straight, the front wagons should have been pulled hard against the inside rail. I fully expected it to come off the track but it didn't.

 

There is clearly a tipping point, where friction, drag, train weight, wheel/flange shape and size plus types of coupling all combine to cause a derailment but I do just puzzle and wonder why in some cases, a long train round small radius curves works and in others it doesn't.

 

I should probably get out more, or get a life, or find something more important to think about! 

[polybear]

13 hours ago, Lecorbusier said:

That really reminds me of one of the layouts on the Right Track DVD ?

 

Do you recall which number DVD?

[Lecorbusier]

16 minutes ago, polybear said:

 

Do you recall which number DVD?

[St Enodoc]

3 hours ago, t-b-g said:

I can accept all that and agree that is reasonable but....

 

So why didn't my 115 wagon train, round tight curves, pull off when it went right round a circuit with tight curves? Were my wheels somehow having less friction than others. Many of the wagons were travelling in a totally opposite direction. The train was heavy and needed a lot of tractive effort to pull it, so as soon as the loco went from the curve to the straight, the front wagons should have been pulled hard against the inside rail. I fully expected it to come off the track but it didn't.

 

There is clearly a tipping point, where friction, drag, train weight, wheel/flange shape and size plus types of coupling all combine to cause a derailment but I do just puzzle and wonder why in some cases, a long train round small radius curves works and in others it doesn't.

 

I should probably get out more, or get a life, or find something more important to think about! 

If you can work out the answer, Tony, you will be in great demand in railway engineering circles around the world!

[Bucoops]

 

6 minutes ago, St Enodoc said:

If you can work out the answer, Tony, you will be in great demand in railway engineering circles around the world!

 

Ha ha very clever!

[St Enodoc]

2 minutes ago, Bucoops said:

 

 

Ha ha very clever!

Thank you. Try the meat pies. I'll be here all week.