4464 Bittern to do 90mph on ECML - 29 June & 27 July 2013

Yes, your point re the physics of higher speed is of course well made.

But Tom, I've tired of arguing the case for accuracy with UK steam speeds, and how often and how fast steam locos went. Suffice it to say there is no proper evidence to substantiate any more then a limited number of UK steam 100 mph runs, let alone A4s running regularly for extended periods at 100mph +. I got taken to task by one of my peers for suggesting 100 mph alone was reached by UK steam as high as 70 times. Even 90mph was not a frequent occurrence until the SR swansong. Schedules rarely required it.

I will find the time one day to list all recorded fast steam running in the UK. The data is around. And it does need summarising in the RPS, (Railway Performance Society) Archives), for all time. And yes, that will no doubt leave out some claimed 100 mph running that was not properly recorded, (but see below).

But I am certainly not criticising you or the majority who do keep talking of the real steam railway as a place where very high speed was commonplace. It is talked of so often unchallenged that it has been accepted as having happened. Hence the need for my detailed work on the subject whilst all those who have the data are still with us, (myself included!).

One example of how these things get into "reality".

There is an excellent and well run web site that has a photo of a Bulleid light pacific speedo some way past the 100 mph mark. The story tells how it was recorded that day at 106 mph by a group of "timers". It has now gone into steam legend along with many other such stories.

I was on that run and recently recovered my long lost notebook with that log in it.

I haven't' detailed the log onto a spreadsheet yet. But it looks like the maximum speed was one quarter of a mile at 90 mph, although the full mile times support an 89 mph max more comfortably. An enormous difference from the speedo photo and the group of "timers" who got so excited at Southampton at the 106 mph run!

The "timers" who put the 106 mph into steam legend were, IMHO, a group of individuals who, at the time, hadn't the faintest idea of how to construct an accurate log. But there are many people around now who will never, ever be moved from the "fact" that 106 mph was reached that day. Especially as the speedo said so!

And that story only emphasises the need for me to find some time to start setting down all properly recorded fast UK steam speeds once and for all. With a few more to be added soon I very much hope!

 

I think you and I are probably basically agreeing but coming from different starting points: you from analysis of actual timed performances, me from thinking about the physics involved. The cube relationship for power needed to overcome drag with speed ramps up incredibly quickly: to go from 75 to 100mph sounds like quite a modest increase, but requires nearly 2.5 times as much power output. Which is why in my days as a racing cyclist, I could ride a ten mile time trial very easily at 23mph when warming up and then would only achieve about 28mph in the race. That miniscule increase of 5mph more than doubled the power output needed.

Tom

 

I'd certainly not argue about the extra power needed to get from 75 mph to 100 mph Tom! I have recorded quite a number of runs where we got above 95 mph, but didn't make the 100 mark. Ran out of grade, time, steam or green signals! Not that such as 35003 on a light load needed much of a grade or even full throttle to get to 100mph. Dreadful shame she wasn't one to be preserved. Not that she defied the laws of physics of course, but she had some sort of inherent desire to run very fast!

Amazing to be having this debate in 2013, started because of steam still running up to 90mph. Who would have thought we would be doing that nearly 46 years ago when SR steam ended.

 

I would agree that perhaps high speed running was exagerated, but also would like to flag up that if it wasn't recorded that doesn't mean that it didn't happen.

I always remember a story my father tells from his time inside at Swindon in the 1960's, he used to talk to a lot of the drivers on Swindon shed and one question he asked was just how fast will they go, the reply was with a wink ' they go a lot faster than people think they will...'

I always heard stories from people who were there that things like the overnight milk and newspaper trains on Brunels Billiard Table were often the chance for drivers to let their enthusiasm go a little, with quieter lines and less scheduling concerns.

 

What difference to a speed recorded by stopwatch on mileposts would 80 yards make?

That is the difference I have found when I surveyed various lines for renewal purposes.
Mileposts are not accurate.

 

Good one Al!

But I have to agree there will be some very fast steam running that wasn't recorded. And sadly that can only ever stay as folklore.

But more usually as soon as steam drivers started to go fast, (anywhere), they attracted timers like Yetis to a Serving Wench! Examples are of British timers such as Sir William Ackroyd, (!!), and other less distinguished Brits being drawn to the USA to time the P&RR P5 "Camelback" Atlantics in 1905 between Camden and Atlantic City. Where some extraordinarily fast running was recorded.

So a great deal did get recorded and not missed.

 

Most if not all proper timers would "learn the route" back in the days of mechanical stopwatches and the use of mileposts. You knew which ones were inaccurate enough to make a difference to the finished log. So any such as one 80 yards out would be ignored. And you would always knew if you had just recorded a "duff" stopwatch time for any reason. It just didn't fit in with the pattern of what was happening at the time. The same as today when a GPS can sometimes throw up the wrong speed just once. You know from the running before and after it has to be wrong.

And the reason you knew others were ok was after numerous times logging the same route. Especially on "average" runs at a steady speed over various sections where you could immediately see an erroneous milepost. Taking passing times and calculating the average speeds afterwards also helped get accurate logs. One of my still missing log books has the very great deal of work a friend and I did between Basingstoke and Woking to get exact distances for obvious timing points at the stations, (like footbridges). Done on runs where, for unknown reasons, (LOL), the crew just wanted to run at a steady 70 mph and keep time, rather than go like the clappers! That told us a lot about station distances and the accuracy of the mileposts.

Inaccurate mileposts is one of the reasons that occasional timers could end up with logs that had totally inaccurate speeds. Especially if they didn't take a whole sequence of passing times to the nearest second over the whole journey, and calculate all the average speeds afterwards to confirm the maximum etc speeds recorded with a stop watch.

There was also safety in numbers! Lots of post mortem examinations with timing friends after any very fast run to check all the detail. Some, like Don, my elder brother, always tried to use the same sequence of 1/4 mileposts for stopwatch times. Noting them all down along with passing times. Which he often took at every full mile as well as normal timing points. That sort of fastidious approach soon sorted out the milepost to leave alone as well as, if not better than, any other system.

The worst one I can remember on any critical stretch was MP 41, between Winchfield and Hook.

I doubt much will bother the legions who will time the A4 90mph runs soon. Experienced timers on a route they know very well indeed using up to the minute GPS and electronic stopwatches. How times have changed!

But I betcha there will some 1/2 mphs quoted Al. I am trying to eradicate them from my old steam logs. Except perhaps for slower speeds over summits.

 

Easy - the percentage error in distance will match the percentage error in speed.

So even ignoring accuracy with which someone can hand time, an 80 yard error over the space of 440 yards is about 18% - that's the difference between 100mph or 82mph or 118mph... Though I guess that would end up pretty obvious if you applied a sceptical look at your own data when you came to calculate speeds.

While you may get an 80 yard error in one pair of mileposts, it is unlikely that this would be cumulative (i.e. over the course of a mile, it is very unlikely you would have a 320 yard error).

In general, the longer the distance you time over, the lower the error, both because the "distance error" is proportionately less (80 yards is a 4.5% error in a mile, but an 18% error in a 1/4 mile) and because the "timing error" is less (a 0.2s error with a hand held stopwatch at 100mph is about 0.5% over a mile; but 2% over 1/4 mile. Note that even a 0.2s error in timing means that you accurately hit the start and end points within 0.1s, which is borderline possible given human reaction times). However, set against that is the fact that the variation in speed is also likely to be much more marked as a mile (or more) is plenty of time for the speed to vary by a few miles per hour.

For example, if a loco is measured to do successive 1/4 miles in 9.6, 9.2, 8.9 and 9.3 seconds, then how fast did it go? Over a mile, it took 37 seconds, which is 97.3mph, plus or minus about 0.5mph for the timing error (and ignoring the distance error, which could add +/- 4 or 5mph to that). In one particular quarter mile, it took 8.9s, which is 101mph, but the timing error is probably at least 2mph even if the mileposts were accurately surveyed. If, as you suggest, they were anything up to 18% out, then who knows? Which I suspect is one reason why the number of genuinely autheticated 100mph + runs is very small, and much lower than many people would like to believe.

Tom

 

In your example Tom, it was not possible to get successive 1/4 mile times in real steam days as I am only aware of one person who tried to use two stop watches, (clipped on a board with a lever over the top I think), to get a continuous read out to 1/10 of a second. I don't think it worked that well!

But a good timer, (especially on his regular timing routes), would have known the crew, their intentions that day, the driving style, the state of the loco, the load, noise from the loco and coach wheels, and the grade. And have a number of other runs at high speed in their "knowledge base". I certainly did. And as you were timing the run you knew what sort of stopwatch readings you should be getting, taking into account the last one you had taken every time. And indeed what sort of passing times you should be recording to balance those stopwatch readings.

Timing errors were not much at all. Most of us had established a technique for using a stopwatch that saw a uniformity in result. The brain's commands to the finger adapted to clicking the watch at exactly the same point each time as the milepost went out of sight past the corner of the window, (or whatever system was used). So any error in that proved to be consistent each time, (and not cumulative), with almost a zero impact on the result. You would be surprised how many runs ended up with all the "top link" of timers getting the same maximum speed give or take a very small amount indeed. Although some of us did sometimes move to half mile stopwatch times at very high speed. But I never saw any significant difference in result doing that: which again pointed to a very well established stopwatch technique where the errors were much less than you indicated.

All of which goes to explain to some extent why "causal" timers who did not have the route etc knowledge could and did end up with outrageous speeds from time to time. Probably taking times from gradient posts as well as mileposts!

Anyway, back on topic. Steam Dreams have just sent out an email flyer saying that on two of the proposed 90 mph runs at least, there are still some seats available.

Not for me, I'm still waiting with a packed bag for information on Breeding Short-Eared Owl locations anywhere in Britain. And with the delays caused by the Spring I could be doing that into July.

 

Whilst the debate rumbles on... There is still one steam loco, which 2-3 times a year does run at a higher speed than 90mph, and is old, and has no such problems doing so..

The green pacific that is my avatar, 18201, Germany of course showing us not just what is possible, was possible or even remains possible... But is actually considered routine... The fact DBS is behind 4464's 90mph exploits is of course coincidence.
But 18201 does run faster than 90mph, and is certified to 99.4mph as permitted... And does so.

Just like any technology it comes down to maintenance regime, to the passengers its a greyhound, but its maintenance regime is like grooming a poodle.

 

Oh yes. I was on the 5th May 2002 run where she reached 102 mph. And I was using continuous electronic timing and a GPS, (my lovely late wife handled that).

At that time I did raise the question of her going up to design speed, 180kmh, 112 mph. Rolling stock was an issue that could be dealt with, but at that time there were concerns about the impact on part of the basic structure of the loco. Personnel changed and nothing became of it.

 

Without opening a can of worms (all right, opening a can of worms), isn't some of the doubt about City of Truro's true speed down to only achieving 100mph in a quarter of a mile timing, with all the attendant error?

Tom

 

Tom,

I think the mods and others will just about tolerate a debate about steam loco high speed here this year of all years. But not a move into THAT debate again. LOL!

Have a look at my web site instead. http://www.germansteam.co.uk/Tonup/Tonup.html

PS. Suffice it to say here that, despite being a SR man through and through, I was brought up on the book "2750, Legend of a Locomotive". And I feel that it is a total tragedy that it wasn't preserved as it most certainly deserved to be.

 

Any inside info please on another test run? Taplow is my usual viewing point (see Tangmere in the snow below) and the timings were published retrospectively of course....

 

Bu..er the A4 timings, we got ourselves a superb photo of a Bulleid here now! LOL. Many thanks.

But, sort of getting back to the topic of speed , I had one actual 100mph run behind an original Bulleid, 34102. And 98 behind her as well. The latter on level track where we accelerated to 98 on the level track. From MP 34 to MP 31 at an average of close to 97 mph. Just 6 cars, but very fine running. Clive Groome driving.

Not sure the A4 will be allowed to go quite as fast! One day maybe.................

 

Also note that 4464 is rostered to work just 2 trains between now and the first 90mph run, and they are both with SD. It was also replaced at the last minute by 60009 today on the Cheshireman, so I wonder if the Southall team are saving 4464 for the 90mph trips?

James at SVN

 

Pretty much hit the nail on the head there, James, its a sensible move not to work her too much leading up to those tours just in case something happened that couldn't be fixed in time, so keeping her wrapped up in cotton wool is the best option............................................ and probably written in blood between all the parties concerned with these runs.

 

Just wondering (and wandering a bit off thread) if Tornado would be allowed to run at 90 mph on the return of the Steam Dreams trip on the actual anniversary of Mallards record breaking run - or if this will remain exclusively to the planned trips with Bittern?