A question about G.W.R. engines

The FR loops used to have a "through road" (the straightest route) and a loop road. Uphill passenger trains had priority for the through road over down trains but down passenger trains had priority over other trains. Minfford, Tan-y-Bwlch and Tan-y-Griseau are right-hand running whilst Penrhyn & Ddaullt (removed) and Rhiw Goch were/are left hand. Down trains used to take the main platform road (left side in direction of travel) at Minfford when not passing other trains but the points at the north-east end now give a straight run into the right-hand road.

 

It actually has nothing to do with Napoleon whatsoever. All of Europe up until about 1905, drove on the left hand side of the road, but some dum French idiot decided the they would drive on the right. And all of Europe folloed suit

 

Although the Americans have always driven on the right the Ford Model T was, apparently, the first car there to have the steering wheel on the left hand side rather than on the right.

 

Which demonstrates that those on the design panel were forced to agree the superiority of Great Western boiler mountings, why else would they logically choose them? They even got to be fitted to diesel train heating boilers, which ensured a supply of such fittings to early preservation projects, many with cocks having Klinger packing sleeves which are keenly sought to this day.
Bob

 

Not entirely true. The official reason given for removal of vacuum pumps on the relative ERO Job number was that they were suspected of causing the fracture of piston rods adjacent to the crosshead, first and foremost a serious technical issue, but conceded that it would have had a cost. The GWR incidentally did not, and still does not, seem to experience similar problems with piston rod fractures.Now in the Great Western application the pump was connected to the brake system via the Vacuum Retaining (VR) valve. This system was quite sophisticated and the VR valve caused the pump to be turned over to evacuating the reservoir side of the brake when an application was made which caused a fall in train pipe vacuum. In the LMS application there was no reservoir and no VR valve, so when an application was made, it required judicious use of the brake valve to overcome the pump trying to carry on evacuating the train pipe, a bit like trying to put the brake on with the large ejector open. Now this problem was magnified considerably when two Stanier engines were double heading and several instances occurred where such doule headed trains passed signals at danger due to an ability to make a sufficient reduction of train pipe vacuum to make a satisfactory stop, and it is believed that this was one of the main contributory factors in the deletion of pumps, but hardly one which could politically be declared.
Regards
Bob

 

This is all true, of course, Bob. But the GWR system certainly was effective, no doubt, but also quite complex, and I struggle to see how such a system which involved a number of moving - and wearing - parts was cheaper to maintain than an ejector, with NO moving parts!

 

You have obviously never had the pleasure of maintaining a GW system. Like all Great Western fittings, the kit lasts for ages and ages and it is very unusual for it to give problems. Major ones are sliding bands ion cylinders and cylinder glands which require occasional re-packing. Brake valves jsut go on and on and need little attemntion as do steam ejector steam valve seats. I c annot remember us ever having to recut a steam valve seat for the last twenty years on 4965 or 5043. If you have ever experienced the maintenance of an LMS standard steam brake valve you might notice a difference. Pipework is substantial and normally gives little trouble, as you would expect from a system working at a higher vacuum - leakage is not a desirable item. The maintenance claims are pretty well true in my experience.

 

I concede the point!

Although I volunteer as a fitter at Bridgnorth, most of my experience, although by no means all, is on LMS types. My user name is a bit of a clue!

 

However, we must also concede that the LMS, a commercial company, had hundreds of each type in service, and found that the GWR one was, overall, more expensive. And they kept very careful accounts...
Perhaps there are issues of scale here - what is true on a fleet of a dozen or so locos lovingly maintained may be different to what happened in the hurly burly of 1930s service.

 

As regard to effectieness of brakes my main concern is not how powerfull they are but how long they last when applied. The guards nightmare is the divided train. 21in or 25in makes mot a lot of odds the two halves will stop' . What matters now is how long will the brakes remain effective. BR, SR, LNER AND LMS used rolling rings in their cylinders which provide a good seal and give a lasting application. The GWR use a wiping seal in their cylinders and these readily leak off. You can almost guarantee that a GW set left overnight will suffer from most of the brakes leaking off. Conversely where a rolling ring is used most brakes will still be applied the next morning

If I did suffer a split train I would rather deal with a 21in system which remained effective whilst looking to recouple the train than a more powerful 25in system which leaked off in 30 minutes

 

When our Hawkesworth Brake Third 2202 went to Bold in 1980 with 5051, she was left standing for 1 day with vac brakes on, they had to be blown down to move the coach. And when on vintage train railtours, the BR drivers would use loco air brake only, to slow the train down, as if they used the vac brakes, the train would stop too early, as the brakes were so effective, compared to BR vac brake trains

 

I have no doubt some GWR cylinders wont leak off. At the SVR we have a good mix of LNER, LMS, BR AND GWR passenger stock. Part of train prep is to pull the strings to destroy captive vacuum to ensure nothing is left at 25in. I know its subjective but experience has shown that more GWR coaches will have leaked off than the others

 

My experience is similar.

 

If sliding band cylinders are properly maintained and fitted with bands of the correct design and grade of material there should be no such problems with them. Do bear in mind that this design was also used by BR and such performance would not have been tolerated by the GWR or for that matter the HMRI. Quiet simply if you have a set which will not stand overnight without leaking off, or which gives the slightest concern about such issues should it divide in trafic, the set should clearly not be in traffic until your maintenance department done something about it, and given the audience which this website garners from various organisations, this is a pretty foolhardy statement to make in public. The very next time that you come across vehicles whose vac brake has leaked off overnight, I suggest that you book them rather than expounding theories such as this.
Regards
Bob

 

I'm not sure that leaking off overnight is a major issue; I suspect much air braked stock would do the same. But if a coach cannot maintain sufficient vacuum to bring a break-away to a stand, that's a different matter.

 

I know the vacuum should stay on for a while, but I was taught to never rely on it staying on long term. When I worked in a freight yard, there was an expectation that anything left for a day or two would leak off.
Once a rake of about 20 presflos were kept in the yard on a Friday night, next service Monday p.m. a shunter on Monday morning pushed a long rake in onto them expecting some resistance to get 700 tons moving. He didn't expect them to stand rock solid with the brakes still hard in, resulting in the first half dozen wagons on his shunt to jump up then land in the dirt.

 

I have tried to ascertain a standard for leakage rates for vac cylinders. I have been plowing through Railway Group Standards and could only disover a standard which required a drop of less than 2in in 5 minutes. Taking this to its mathematical conclusion20inches will drop in 50 minutes. There appears no standard which requires a vac cylinder to remain on overnight. If someone can show me such a standard I will eat humble pie.

Berthed trains are required to be secured by handbrakes or adequate scotches. The automatic brake, air or vac, must not be relied on. In the case of the Great Central runaway the RAIB highlights the failure of the scotch and non use of the loco handbrake. That the loco air brake failed is mentioned in passing but appears not to be central to the report (R042015_150521_Loughborough_Central

 

Can't speak for Apple, but, smiley or not, your comments re GWR locomotives are complete cobblers, speaking from 40 years experience.

 

Correct. For coaching stock:—

BR 10906 - (1969) - 2" in 5 minutes;
CMS 123 - (1988) - 4" in 5 mins;
CEPS 1019 - (1990) - 1/2" in 15mins

CMS 123 is widely touted as the standard to meet.

Pete S.,
C&W Dept.,
GWS Didcot

 

If I have understood this correct a Left Hand Driving locomotive the driver will be standing at the right side at the footplate?