Midland Railway Company

[WFPettigrew]

5 hours ago, Compound2632 said:

So I'm wondering what was the point of the direct-acting valve set at 5 psi above the Salter valves

 

Salter valves are an imprecise science, they don't just "blow" at the pressure set, but start feathering well before it.  And they don't open far enough even when they are blowing to stop further rises in pressure.  It's only a small over-rise* but it certainly can happen.

 

Obviously the MR felt it would be wise to have a second set of valves to prevent any further rises.

 

This "feature" of Salter valves is why things like Ross Pop valves were invented, which do not feather (OK they might wisp a bit but nothing major), but then open very sharply with a wide aperture, and close equally abruptly, designed to both stop over-rises in pressure and to alarm small children. 

 

All the best 

 

Neil 

 

* And before anyone gets alarmed, remember that boilers are designed for more than their working pressure, that all boilers are nowadays hydralically tested to double their working pressure (with the safety valves blanked off, obvs), and that all boiler inspectors who approve 14 month tickets for boilers with Salter valves are well aware of this feature of these valves and make their decisions accordingly. 

[Dave Hunt]

On 24/11/2023 at 21:08, jamie92208 said:

I look forward to it as well. I hope that you are far enough away from the thing with a copper capped

Chimbleys not to get Infected. 

Jamie

 

I hate to be the bearer of bad news, Jamie, but the Baldwin 2-6-0s (one of which graces your layout) had copper capped chimneys; it's just that they were painted black.

 

Dave

Edited November 27, 2023 by Dave Hunt

[Dave Hunt]

33 minutes ago, WFPettigrew said:

 

Salter valves are an imprecise science, they don't just "blow" at the pressure set, but start feathering well before it.  And they don't open far enough even when they are blowing to stop further rises in pressure.  It's only a small over-rise* but it certainly can happen.

 

Obviously the MR felt it would be wise to have a second set of valves to prevent any further rises.

 

Two other points about Salter valves acting on the dome and shrouded direct valves on the firebox:

 

1. Salter valves on the dome can be fiddled with; shrouded valves can't.

2. If the direct valve, set nominally to 5psi above the Salter valves, starts to blow, it is an indication to the footplatemen that something has to be done to bring the pressure down.

 

Dave

[John-Miles]

On 26/11/2023 at 15:07, jamie92208 said:

...... the sections through stations at about 1 in 270, which I was told was a Board of Trade requirement. 

 

Jamie

I don't think this can be true. For instance near where I live there is the delightfully named Dingle Road which is on a 1 in 40 and even if the gradient diagram is slightly out you can see it is well over 1 in 270. There are plenty of other examples in South Wales of stations on steep gradiemts and of course there is Five Ways which IIRC is on a 1 in 80.

[WFPettigrew]

1 minute ago, John-Miles said:

I don't think this can be true.

Seconded - Haverthwaite station on the Furness is 1:75 through the platforms, just to give one example from round this part of the world. 

 

It is certainly true that in more recent years, stations were and are required to be relatively flat and relatively lacking in curvature: there was some talk about reinstating a station at Furness Abbey near Barrow twenty years ago, but nothing came of it because of the curvature, and there were no "grandfather rights" to re-use the original station because the platforms were demolished after it closed. 

 

Quite when such restrictions were brought in, but I think it was well after when the majority of railways were built in this country. 

 

All the best

 

Neil 

[jamie92208]

I based my observations after the experience of looking at deposited plans for various Midland Railway projects from the 1870's to the 1890's.  A lot of these lines had long stretches of 1 In 56 but at Station locations there were short stretches of 1 in 270.  Possibly the requirement, certainly on the Midland dates from about 1870.  The S & C plans were surveyed in the mid 1860's so possibly predate this.  I am very happy to be corrected. 

 

Jamie

Edited November 29, 2023 by jamie92208

[Compound2632]

5 hours ago, jamie92208 said:

I based my observations after the experience of looking at deposited plans for various Midland Railway projects from the 1870's to the 1890's.  A lot of these lines had long stretches of 1 In 56 but at Station locations there were short stretches of 1 in 270.  Possibly the requirement, certainly on the Midland dates from about 1870.  The S & C plans were surveyed in the mid 1860's so possibly predate this.  I am very happy to be corrected. 

 

I shall correct you to 1 in 260! See Section B Paragraph 16 of the Board of Trade Requirements:

https://www.railwaysarchive.co.uk/documents/BoT_Requirements1902.pdf

This is a slightly tricky version of the document to follow, as it's got "track changes" on (roll over, Microsoft) for revision of the 1885 version for issue in 1902, allegedly, though the print date is 1892. Anyway, it's the usual case that the rule is to be strictly followed except in cases where it won't stick.

[kevinlms]

2 hours ago, Compound2632 said:

 

I shall correct you to 1 in 260! See Section B Paragraph 16 of the Board of Trade Requirements:

https://www.railwaysarchive.co.uk/documents/BoT_Requirements1902.pdf

This is a slightly tricky version of the document to follow, as it's got "track changes" on (roll over, Microsoft) for revision of the 1885 version for issue in 1902, allegedly, though the print date is 1892. Anyway, it's the usual case that the rule is to be strictly followed except in cases where it won't stick.

I'll ask questions on this later, so I hope you memorise it!

 

What an awful document - didn't they have a typist in the office to redo it?

[jamie92208]

6 hours ago, Compound2632 said:

 

I shall correct you to 1 in 260! See Section B Paragraph 16 of the Board of Trade Requirements:

https://www.railwaysarchive.co.uk/documents/BoT_Requirements1902.pdf

This is a slightly tricky version of the document to follow, as it's got "track changes" on (roll over, Microsoft) for revision of the 1885 version for issue in 1902, allegedly, though the print date is 1892. Anyway, it's the usual case that the rule is to be strictly followed except in cases where it won't stick.

Thanks very much for that Stephen, at least my memory isn't too fallible.  On the deposited plans the stations weren't shown but could be interpolated (I think that's the right word). From the gradient profile.  That version is obviously some sort of consultation document for the revision of a previous set of regulations.  I was looking are a paragraph at the end containing what IIRC was called Revisions and repeals.  This would tell you what previous legislation was being altered. I will dig out the notes that I made when I wrote my article about the unbuilt West Riding Lines in Midland Record.    It's a long long time since I did law research.  

 

As the gradients showed on the deposited plans the requirements must have been in the Parliamentary standing orders for the submission of private bills for new Railways. 

 

I wonder if there had been a runaway at a station in the early 1870's.

 

Jamie

[Compound2632]

4 hours ago, kevinlms said:

hat an awful document - didn't they have a typist in the office to redo it?

 

It's a document in course of revision, laid out to show both the deleted text and the revised text substituted. What interested me about this was that it demonstrates that Microsoft Word's "track changes" is faithful to established typographical practice.

[DenysW]

3 hours ago, jamie92208 said:

I wonder if there had been a runaway at a station in the early 1870's.

I though that the principal thrust of the rules was to stop runaways during shunting, so uphill shunting might be OK, but downhill wasn't.  This comes from comments read a while back about stations on the steeper part of the Lickey Bypass line through Redditch that apparently failed this logic - but weren't rebuilt.

 

I also feel that what numbers there are imply that the bearings on Victorian wagons provided a resistance to motion at about 0.5% of the weight of the wagon once rolling, so 1 in 260 (o.n.o) would be enough to slow wagons back to a stop.

[Compound2632]

7 minutes ago, DenysW said:

I also feel that what numbers there are imply that the bearings on Victorian wagons provided a resistance to motion at about 0.5% of the weight of the wagon once rolling, so 1 in 260 (o.n.o) would be enough to slow wagons back to a stop.

 

I feel an A-level Physics question coming on...

 

A gradient of 1:260 is 0.38%, so that's the percentage component of the weight in the direction of motion. 

 

 

[jamie92208]

23 minutes ago, DenysW said:

I though that the principal thrust of the rules was to stop runaways during shunting, so uphill shunting might be OK, but downhill wasn't.  This comes from comments read a while back about stations on the steeper part of the Lickey Bypass line through Redditch that apparently failed this logic - but weren't rebuilt.

 

I also feel that what numbers there are imply that the bearings on Victorian wagons provided a resistance to motion at about 0.5% of the weight of the wagon once rolling, so 1 in 260 (o.n.o) would be enough to slow wagons back to a stop.

That's probably correct, there was an accident at Keighley caused by a runaway from a shunt on the Worth Valley Line. 

 

Jamie

[DenysW]

7 minutes ago, Compound2632 said:

I feel an A-level Physics question coming on...

I've seen it asserted that there have been (many?) more than 50 equations proposed for the rolling resistance of stock as a function of velocity, so A-level probably isn't enough to get better than simplistic rules of thumb like mine, above. There's also the frictional equivalent of inertia from those bearings to resist the start of wagons moving. But if they've just been bashed by a shunting engine that part's over and done with.

[jamie92208]

I've just checked my notes for the article on unbuilt lines in the West Riding in Midland Record no 21.  The Bradford Halifax  and Huddersfield Railway was proposed by the Midland in 1877 but fell in Parliament.  IIRC, mainly because the GNR Queensbury Lines duplicated much of it. It would have left Forster Square via a triangular junction at the end of the platforms.  It climbed to it's summit, which was in a tunnel under Denholme, at a steady 1 in 56. No stations were marked on the plans but there were I think three sections at 1 in 260 where they would logically have been. One was at Clayton and another near Thornton.   I think that the other was in the Bradford suburbs near where City Road Goods depot was built by the GNR.  I would seem that the lower gradient provision was certainly in force by 1877.

 

I don't have the research facilities near me but something obviously prompted the change. 

 

Jamie

[Compound2632]

1 hour ago, DenysW said:

I've seen it asserted that there have been (many?) more than 50 equations proposed for the rolling resistance of stock as a function of velocity, so A-level probably isn't enough to get better than simplistic rules of thumb like mine, above. There's also the frictional equivalent of inertia from those bearings to resist the start of wagons moving. But if they've just been bashed by a shunting engine that part's over and done with.

 

The physicist assumes an ideal wagon with constant resistance to motion.

[WFPettigrew]

30 minutes ago, Compound2632 said:

physicist

What have physicists, done to upset RMWeb this week?!

[DenysW]

3 hours ago, Compound2632 said:

The physicist assumes an ideal wagon with constant resistance to motion.

The empiricist says "O bleep*. This means we've got to measure it, and properly at that. And re-measure whenever we change stuff like bearings. Bleep*"

 

* Insert profanity here.

[Holmesfeldian]

Some choice Midland locomotives and rolling stock are coming up for auction...

 

https://www.the-saleroom.com/en-gb/auction-catalogues/special-auction-services/catalogue-id-srspe10578?searchTerm=midland+railway&whereToSearch=%2Fen-gb%2Fauction-catalogues%2Fspecial-auction-services%2Fcatalogue-id-srspe10578

[Crimson Rambler]

I think the discussions have covered most of the points concerning the safety valves on Mr J's smaller boilers. I would however add that SWJ was reputedly a cautious man who liked to advance in small stages. The presence of a lock-up safety valve gave an indication to the world if the Salter valves had been tampered with, for if they were not blowing but the lock-up was, then something was wrong. As pointed out the latter was set to lift at 5lbs/sq in higher pressure.

 

But why fit in effect two systems? I believe Mr J preferred to have what normally would be the main safety valves located on the barrel so their operation reduced the chance of water being picked up with the escaping steam. The ebullition is far more violent around the firebox where typically around 60-75% of the steam was generated - with the balance of course coming from the barrel. If water is picked up it makes a great deal of mess – to the engine, the surroundings and any unlucky people in the vicinity.

 

The smaller boilers such as the A, B, C, D, E and F were fitted with four gusset stays which tied the firebox outer wrapper plate to the outer door plate (backhead). They supported the area of doorplate above where the direct stays ceased. The steam load on the roof of the inner firebox was carried by typically eight sets of roof girders running fore and aft in the steam space. These girders were supported in turn by hangers whose upper ends were connected to a pair of circumferentially disposed tee-irons curved to suit and riveted to the inside of the wrapper plate.

 

The intention was to obtain adequate support for the inner firebox while providing flexibility to accommodate its growth and movement in service. However the downside of this design was that there was a lot of 'structure' above the crown potentially restricting access to it for descaling so the manhole carrying the lock-up valve greatly improved the access.

 

These designs of boiler only contained two washout plugs above the crown - these were fitted in the doorplate left and right roughly at about the working water level. There were none fitted in the firebox wrapper plate although some of SWJ's earliest Midland boilers had been fitted with what has been called a mid-feather. It resembled a transverse radial groove fitted into the inner crown plate with the intention of introducing flexibility. Boilers so fitted can be readily identified by the presence externally of a circular cap located roughly halfway along the firebox and 9-10ins or so below the handrail. This detail did not last.

 

 

Crimson Rambler

[Crimson Rambler]

I was asked if I would help man the S7 stand at Warley Exhibition on the Sunday. This was something I was happy to do, indeed it reminded me very much of the earliest days of the S7 Society.

So I took my toy train for a jolly to Birmingham which necessitated it being temporarily assembled in order that it looked something like a locomotive rather than the collection of funny shaped lumps that represents its normal condition.

 

While in this condition I took a few piccies before it is dismantled again to permit the boiler clothing plates to be fitted and what the Midland called the moulding pieces to be added in the cab around the firebox.

 

 

Since my last post I have removed the ABC Mini Gooch motor/gearbox combination and substituted one of Slater's final drive 'boxes - a solution I much prefer because it is more compact and permits the introduction of some flexibility in the drive line thereby enabling the trailing axle to be given a bit of movement via its Slater's horn guides. Unfortunately this substitution has left a huge hole in the back of the firebox/ashpan which would not have been needed if ....

 

 

The replacement nickel silver cab floor is visible in one of the views. Its rear corners are provided with two 'ears' which locate within what would have been the O gauge wheel slots if the platform (or running plate) had been used as the kit designer intended. This, in my opinion represents an important advantage of S7 – while it represents a gain of only one millimetre on the gauge it delivers over 2 millimetres on the wheel back-to-back dimension.

 

 

 

The cab steps are wonky because they are just wedged in.




Crimson Rambler

 

[jamie92208]

3 hours ago, Holmesfeldian said:

Some choice Midland locomotives and rolling stock are coming up for auction...

 

https://www.the-saleroom.com/en-gb/auction-catalogues/special-auction-services/catalogue-id-srspe10578?searchTerm=midland+railway&whereToSearch=%2Fen-gb%2Fauction-catalogues%2Fspecial-auction-services%2Fcatalogue-id-srspe10578

Good heavens I better go and check in the shed, I've got one of each of those Locos. 

 

Jamie

[Dave Hunt]

8 hours ago, Crimson Rambler said:

I was asked if I would help man the S7 stand at Warley Exhibition on the Sunday. This was something I was happy to do, indeed it reminded me very much of the earliest days of the S7 Society.

So I took my toy train for a jolly to Birmingham which necessitated it being temporarily assembled in order that it looked something like a locomotive rather than the collection of funny shaped lumps that represents its normal condition.

 

 

Now that's what I call washout doors.

 

Dave

[Crimson Rambler]

@David Hunt Do you think SWJ missed a trick concerning boiler washouts?

 

Crimsom Rambler

[Tom Burnham]

On 30/11/2023 at 01:53, kevinlms said:

 

What an awful document - didn't they have a typist in the office to redo it?

It would have been a Lady Typewriter!