Brighton Atlantic: 32424 Beachy Head

Michael, re your aside on no on time arrivals at Southampton on the non-stop 08.30 ex Waterloo on 30 runs. May I please add the following to that comment, for the benefit of those who don't know the timetable on that route.

From 1962 to the start of electrification works in June 1965 I never had an on time arrival at Southampton on any down 'two hour (to Bournemouth) express.' They were, from Waterloo, the 08.30, the 10.30 and the 12.30 Bournemouth Belle all pullman car train.

That was primariry due to the Portsmouth-Salisbury demu booked just in front through the one line each way bottleneck over the short, circa one mile section, from Northam Junction until just before the platform roads at Southampton Central.

After electrification work started in June 1965 those expresses generally had a 93 minute schedule (instead of 81 or 82 minutes) to Southampton - I am talking public timetable times. But with the demus still running through Southampton at their previous times, there was a much longer gap until the down expresses used that one line each way section. But, other delays were available! Eastleigh and onwards being the usual culprit, so much so that I think I am about to type up (for my SR steam loco memoirs book), the first (and possibly only) time I ever had an on time arrival at Southampton on a non-stop express from Waterloo, and that was on 31 December 1966. That was with 34093 on the down Bournemouth Belle - 9+2/419/450t - with the crew of Gordon Porter and Tommy Moult, along with Brian Smith. Arrived Southampton in just over 89 minutes, so circa 4 early. Typical of so many runs in those last couple of years, probably lack of a washout and/or rubbish coal saw boiler pressure down to 140 psi by Hampton Court Junction, again down Roundwood bank and as low as 130 psi at a location that I still need to be able to read correctly from my notes. My notes also state full and and 25% on the 'level' stretches - running to Basingstoke may have only touched 70 mph once, then a period of trying to recover steam with 50 mph or less from Worting Jctn to Micheldever, which was used when were back to full and 25% from Wallers Ash box, with around 85 mph at Shawford - before Eastleigh etc did their best, but failed, to stop our early arrival at Southampton Central. Loco information from Brian Smith (who we very sadly lost recently) after arrival at Bournemouth Central. My log not yet put on a spreadsheet to check all the times etc, but that won't change the early arrival at Southampton.

Here endeth the sermon - back to 32424!

Bryan B

 

That comment about lead is interesting, but my hunch is that it needed less, not more - hence running better with a longer cut off.

On a Stephenson valve gear engine, normally the lead increases as you shorten the cut off. That's normally a good thing assuming you only decrease the cut off as the speed increases. The lead steam provides a cushioning effect to the piston near the end of its stroke; the faster you are going, the more momentum it has so the more cushioning you want, and so the more lead steam. But there is a more subtle point, which is that the lead is essentially a measure of how big the port opening is - but the faster the loco is going, the shorter the time the port is open. So the effects balance out: at high speed, you shorten the cut off, get a bigger port opening for lead steam but it is open for a shorter time because you are going faster.

The significance of that, particularly on a loco with Stephenson valve gear, is that if you pull it up too tight at low speed, you get a big port opening that is also open for a long duration, and the effect is you get too much lead steam - so much it tries not just to cushion the piston, but to actively try to reverse it before the extremity of its stroke. You can feel that in a knocking in the loco - if you feel that, you have pulled it up too tight.

The Atlantics, in addition, have big wheels, so the number of rpm is comparatively low - which means at a given linear speed and cut off, the port stays open for longer. That will exacerbate the problem of too much lead steam. (All else being equal, an Atlantic doing 40mph has the same wheel rpm - and therefore duration of valve opening - as a loco with 5 foot wheels doing 30mph).

So my hunch above is that on the outward journey at 30%, it was pulled up too tight for the speed they were going; running it at 40% on the return journey with less regulator gave it a smoother ride since there was less lead steam trying to resist forward progress.

On regulator openings: I never quite understand what terms like "2/5" or "4/5" refer to - presumably how far across the regulator quadrant the regulator is pushed? (That would be easy for a footplate observer to see and make a note of). That's not necessarily a straight proportion of "position = steam flow" though. Most of our engines have a first and second valve to the regulator, with varying proportions, so we'd more commonly think in terms of "first valve just open - full first valve - big valve cracked - big valve open - fully open". From a fireman's perspective, there is a rise in water level when the regulator opens, and another rise when you go into big valve. That rise when you go into big valve is I think something like 3 - 4 inches (relative to the regulator shut position), hence the injunctions we have about keeping the water level in sight, due to the very high gauge glasses and low boiler fittings. My hunch is that for the fireman, control of the water level may have got tricky at regulator fully open in big valve, and there may have been more risk of priming and / or picking it up through the safety valves too.

The two effects might explain why they had a better time of it on the way back at longer cut off and less regulator opening. Bear in mind as well that the 150psi they had feels a bit "down the pan" for a loco with a 200psi boiler, but is "actually not too bad" when you only have 170psi, as they were built with! It does go to show there is a lot more art to it than just assessing locomotive performance in how quickly you can get from A to B.

Tom

 

Tom,

Do you know for how long 32424 is going to be carrying the totally unnecessary "The Bluebell Railway" headboard? Now the press reports have been written and publicity shots taken, surely there is no need to deface the front of this fine loco any more. After all, I doubt if the visitors are confused as to where they actually are and think they're on the Settle & Carlisle or the Trans-Siberian Railway!

I'm looking forward to seeing this fine loco in action and to get a picture or two - perhaps even on Monday when you're on duty - but am quite happy to bide my time until the headboard has disappeared.

Thanks

 

The LMS 3-cylinder locos ended up with a fixed lead of 5/16"(and relatively short lap) which I doubt is less than the variable lead of most Stephenson gears at 30%, plus they had big wheels. You have commented before on here of your experience of the effects of pulling up Stephensons at low speed on Bluebell locos and I wonder whether this effect is so noticeable on the LMS 3 cylinder locos? - logically it should be.

 

In terms of lead, notching up is going to make little difference with Walschaerts valve gear. You are going to get the admission of steam for the same length of time whatever the reverser position. There's a big 'but' to this, though. With most valve gears notching up (or down) affects much more than the point of cut off of steam in the cylinder. It also affects the point of release and the point of compression, both of which get earlier as cut off is reduced. The former, by releasing steam earlier, reduces the forces on the piston and hence the wheel so would reduce the tractive force. Having an early release of steam can be advantageous at speed as it gives more time for the steam to leave the cylinder but not at low speed. If it hasn't exhausted by the back stroke it effectively becomes a counter-pressure engine, creating a braking effect but, at low speed it is wasted energy up the chimney. The earlier point of compression is, in essence, acting in the same way as lead steam as it provides a counter productive force.
Information on LMS 3 cyl locos and their valve gears seems to be sadly lacking in my library so I can't comment too much further on them.

 

Whee you set the reverser and regulator can become a whole MIC subject. To move a train at a given speed requires a certain horsepower and the faster you g othe more horsepower you need. Horsepower in a cylinder for any given speed can be calculated by the formula: P.L.A.N./33000 where P = mean effective pressure, L = length of stroke and N = speed in RPM Now all these are constant for any given situation, including the MEP. There are two ways for the driver to achieve a given MEP; one is to fix the cut off and vary the regualtor setting; the other is to fix the regualtor setting and vary the cut off. as shown in the diagram below. The two methods will give different steam consumptions for the same horsepower.


In reality, these two lines cross over and the point at which they cross determines when it is better to use a longer or a shorter cut off to get most out of the engine. These lines are known as Willan's lines and, in reality they will vary from loco to loco.



This should help to explain why different regulator & steam settings can make a difference to the steam consumption and hence the firemans efforts, even when the load and all other conditions are equal.

 

I visited on Friday and duly had my rides both ways behind Beachy Head. Hearing her in the flesh(?) confirmed just how loud the air pump is, but I also noticed just how quiet Fenchurch's is. Can anyone explain why there is such a great difference?

 

32424's is larger, but also the locomotive frames may well act as an acoustic amplifier. Tom?

 

Fenchurch has the smaller size pump, has lower pressure steam going into it, and has a longer exhaust route. I wonder if the Atlantic pump is loud as presumably it discharges straight from underneath up the chimney rather than going along the boiler first

 

Some footage of the Brighton Works Weekend, with newly-built LBSCR H2 Atlantic 32424 'Beachy Head'. Even in the wet weather she looks absolutely glorious!

 

A few impressions of firing Beachy Head at the weekend. Again, I should stress (1) I still have very little experience, so views may develop and (2) I can't comment on anything about driving. In particular, à propos the earlier discussion about cut off, I didn't really look to see what the numbers were. The reverser indicator markings aren't especially prominent from the fireman's side of the cab, and I was more occupied with my stuff than to start going over for a close-up look at critical points. The loco did need second valve to get to / maintain line speed on our gradients.

The duty was prepare the loco + small carriage shunt + two round trips to East Grinstead, nominally non-stop in the up direction (though we got checked by signals on each trip); then hand over to another crew. The driver had the same basic experience as me, i.e. a prior familiarisation trip to Horsted Keynes, so we had one of the workshop staff ride with us who was able to provide lots of useful advice to us both. In addition, the loco has come with quite copious notes, but seeing things in practice you have hitherto only read about is massively beneficial.

Load was four Mark 1s + LNWR Obo, 177 tons tare, or 8 tons below the load limit. Weather was mostly dry, but we did have a drizzly rain to start on our second trip leaving from Sheffield Park, which soon dried up.

Prep: The current coal (a mixture of real hard coal and ovoids) burns mostly to ash. Raking through the fire left from the night before caused most of it simply to fall through into the ashpan. So there was comparatively little clinker left, none of which was stuck to the bars. I got out about 1/2 of a barrow with the slice - not much given the size of the grate. Because the grate is short, the fire irons are proportionately short - and therefore light. So slicing out the remains of the old fire was surprisingly easy. In comparison, the S15 or Hall which have similar grate area, but long and thin, are far worse.

The advice on lighting up pretty well matched what I would have done anyway, i.e. one layer of coal all across the grate and just let it take its time. At the point of lighting up we had about 50psi from the night before and it came round easily to about 115psi with no further attention or coal, no blower and no damper opening. At which point, we could test the injectors, blow down and then run the ashpan spray when refilling the boiler. I then opened the damper to go underneath to rake out the ashpan. The ashpan itself is huge but nicely unencumbered. There is only a front damper, so everything has to be raked out forwards, but apart from the volume, there was no difficulty there. Give me that over a hopper ashpan any day! The extra air from the wide open damper bought the pressure up quickly to about 150psi by time I had finished underneath. Time to wash and get changed.

Shunt: We had a shunt to perform after going off shed. Because 72 had been swapped for 65, the set was strengthened with 7598 (the Brighton bogie first) so it was a bit more protracted than diagrammed, but not much for us to do other than follow the shunter's instructions; and an opportunity to watch how water levels moved around on gradients etc. (The sidings leading into our carriage shed are down hill).

Trip: The loco has a GN-style firehole door which opens right up, with a flap in the middle to fire through. Practice is not to open the door when the regulator is open, but just to fire through the flap. The only other loco we have with a similar arrangement is Birch Grove, but without a wide firebox, plus it hasn't been in traffic for a few years. So the advice was to bank the back corners right up, then fire to the sides keeping the rest fairly thin. The gauge glasses are quite tall - probably about 8 inches - but have a "do not fill beyond this line" mark about 2/3 of the way up, so psychologically you treat that line as "full" when sat at a station. With the main door open, I packed both back corners, down the sides, a bit under the door, thin at the front and in the middle. We left on our first trip (I think about 6 or 7 minutes late, due to knock-on impact of the delayed shunt) with the water on the line and pressure just about 170psi. Up Freshfield Bank the pressure easily stayed in the 165 - 170 mark with the damper on the first or second notch, and the flap part open to control the smoke. First valve seemed to raise the water about an inch; second valve gave it another two inches or so of lift, and the gradient a bit more i.e. about four - five inches in total change from "second valve up a hill to regulator shut down the other side". So that put the top of the water around the top nut. I only put the injector on at the bridge near the top of the bank; and when the driver shut off we had about three inches showing on the descent towards Tremains crossing, i.e. loads. As for firing, I'd say 90% was to the sides with occasional rounds to the middle. You have to dance around a bit to hit each side through the flap - made harder on the right hand side by a heat shield for the driver's legs which impedes your throw from the left towards the right - so there is a bit of technique. Everyone will have their weak areas firing: for me it was hitting the front left corner (i.e. on the driver's side) but fortunately it didn't need much down the front.

I'd thought about opening the big door to top up the back when running through Horsted Keynes, but there was no chance, since the driver opened up through the platform immediately after swapping tokens. But more of the same worked: keep firing little and often to the sides, keep the top of the water in sight, run the injector if it looked like blowing off. We kept between 160 and 170 like that all the way until running through the tunnel when pressure fell off to about 150 psi. Water level was fine, probably a notional half glass that could be recovered on the drop down to Kingscote. I did use that opportunity to top up the back corners, probably another two or three in each corner. The one oddity is that having rebuilt the fire, it seemed reluctant to come round until the driver opened up for the little pull into Kingscote, at which point everything came alive. From Kingscote, we had water just below the line at the token exchange (regulator shut, level in the platforms); then maintained about 160psi on the first trip and 165 on the second, all the way up in the big valve and it was an exercise of "no, you still don't need it ..." I think I put the injector on each time at the first bridge just before the summit with the water about an inch or so below the top nut. Lose three or four inches shutting the regulator and another for the gradient effect and you still end up with a decent level across the viaduct while still having some space at the station. I think we stopped with about 145 psi and a nominal half glass (i.e. half way to the line) on the first trip; and about the same water and 150psi second time.

We didn't recover any time from our late start, but didn't lose any more either, despite a signal stop on the Horsted Keynes outer home on the first trip. The gradient there is 1 in 75 up, but we got away from a stand without a slip, but with probably about 140psi on the steam chest pressure gauge.

Coming back - not much to say, except it is probably going to be blinking cold in the winter running backwards on a cold day, and worse in the wet.

The striking thing is how little water it uses. Do the same non-stop trip on the O1 and it is lovely - but you are in a constant battle to get water into the boiler, because you know if the driver is in the big valve, you are gradually losing the race with one injector running. Whereas on the Atlantic, it was a constant mental battle to keep telling myself "no, doesn't need any - no, not yet - still not yet".

Tom

 

Tom, a fabulous report, thank you so much for taking the time to write that.

Bryan B

 

Facinating account Tom and very interesting. Your last sentence says it all - what a good steaming boiler you have there. But.....opening the big door to fire through when out on the road? Surely not. I'm sure that you guys will soon master the art of firing as intended through the flap. Unless something has gone seriously wrong you would not normally open the door from the loco coming off shed to returning at the end of the day. But that will all be part of an interesting learning curve on a new and interesting loco. All part of the fun/challange of being a heritage engineman.

Peter

 

No, certainly not while the regulator is open. In time we’ll get a technique that works. I assume you’ve got to get the blade in flat, then roll and flick to the side?

I’d love to see how the SR men of old did it; I think the run to Newhaven would not have been an easy job.

Tom

 

The one thing that surprised me, was how high up the fireman has to lift the shovel to fill it with coal from the tender, before firing the loco. So used it being at almost ground level.

 

The oiling can looks surprisingly unbattered - well used, patinated but not apparently dented.
In fact just what I would expect a Brighton driver to pose with, tidy and like Stroudley, wearing a bow tie.

 

Interested to know what injectors have been used on the loco?

You're obviously not used to firing LNER pacifics, Tom. Getting the back corners filled through a tip flap door is relatively easy. You need to get the whole shovel blade through the door then lower the shovel handle to the right or left, as required and flick the coal backwards. That's really no different than with a conventional sliding door set up as, with that, you have the flame scoop in the way, which doesn't exist on a tip flap. One bit of advice is don't overload the shovel; it's much easier with one half full. It's often better to wear a glove on the hand that gets near the firehole door as it does get fairly close.

As to running backwards on a cold day, surely it is no worse (or better) than an S15?

 

My video from the Bank Holiday Monday of theBrighton Works Weekend, with some additional shotsfilmed on Tuesday. Mostly focusing on 34059 &32424 with one shot of the O1 filmed over two days. A lovely couple of days, what a fantastic achievementBeachy Head is, having watched it being built overmost of my life it was brilliant to see her running, huge congratulations to everyone involved. Photos to follow.

 

I recall reading somewhere that when the 9Fs were allocated to 35A New England (Peterborough) that the firemen on them couldn't get used to the sliding firehouse doors, so much so that they were fitted with the LNER type that they were used to.

 

In Peter Townend's book 'East Coast Pacifics at work', he mentions on pg. 169 this fact about the LMS swing door having to be altered to the LNER arrangement before the crews would accept them at New England shed.