Welsh Mountaineer, 4th August

When the problem is slipping, as it was this time and on the occasions in 1999 and 2009 when I was behind steam on that line, then the critical factor is the total adhesion weight of the loco, with an additional slight disadvantage for any loco with trailing wheels. How do the adhesion weights of the Stanier Class 5, the Standard 4 tank, the 8F and the K4 compare?

 

Isn't the extra set of drivers on the 8F gripping the rail also a factor ?, 8 is better than 6.

 

The adhesive weight is only one part of the equation. The 8F has 62 tons whereas the K4 has 57 tons 18 cwt. The Mogul has a significantly higher nominal tractive effort 36,599 lb as opposed to 32,438 lb. This might lead an observer to believe that the LNE design must be lighter on its feet so to speak. The key is the number of cylinders. The GWR 28xx has an adhesive weight of 68 tons 10 cwt and a nominal tractive effort of 35,380 lb, the NE T3 has an adhesive weight of 71 tons 12 cwt and a nominal tractive effort of 36,909 lb and we all know that GW engines are the best when subjected to a test trial, don't we? Well if you are wanting to move a heavy load over a difficult route then out of the second pair of engines you would be best advised to take the three cylinder design (though I do very much admire the Great Western machine).
In those countries where mountainous routes are the way of life smoothness of power delivery has frequently been judged to be very important. The K4 is a three cylinder simple design, as is the T3. A lower factor of adhesion is more acceptable in a three cylinder simple than it is with a two cylinder. The difference between the peak tractive effort and the mean is less for the three cylinder type, you do not want a peak breaking the coefficient of friction that you are dealing with. The T3 will take a full gear, full regulator on a gradient of 1 in 75 hauling 755 tons not just for a few minutes but for half an hour and more. As for the K4 it will comfortably deal with combinations of load and route far beyond what a casual observer might be lead to believe possible because this is what the design was built to achieve - it may indeed look smaller than the coaches that it hauls but loads of twelve and more present it with few problems over moderate routes. For the Conwy Valley route with the engines to be found within the approved lists, if you are wanting to work six coaches with a significant degree of certainty there are only two to choose from.

 

More drivers means more adhesion weight for a given axle load, but it's surely the total adhesion weight that matters.

Agreed.

 

Tricky, complicated things these steam locomotives. They appear to be so simple ....... If the civil engineering side dictates you have to head down the more axles route in order to obtain more adhesive weight and so make use of a higher tractive effort. Getting the civil engineers to understand the advantages of a three cylinder design in terms of better balancing and reduced hammer blow proved to be extremely difficult on occasion.

In general terms you need more adhesive weight to prevent a two cylinder engine from slipping than you do a three cylinder. Or for a given adhesive weight you can factor in a higher tractive effort with a three cylinder design than you can with a two cylinder. Or, beyond a certain limit, for a given tractive effort requirement you can build a more compact three cylinder design than two cylinder. Similar problems occur when comparing compound expansion locomotives with simples. Compounds deliver a smoother output, when two cylinder equivalents have been produced for comparison trial purposes the propensity for slipping has become close to unmanageable.

When introducing more axles into the equation you then have the nature of the routes to be worked to be considered, the curvature and how to negotiate it. You can reduce driving wheel size and so reduce fixed wheelbase. Or you can design a more complicated and expensive machine with controlled lateral movement of the axles. A mechanism much used in the world but not popular in the UK. Having reduced driving wheel size will your design be able to run fast enough to maintain a commercially acceptable schedule? In the USA 110 mph with 5' 10" driving wheels was acceptable with two cylinder machines, would that be countenanced in the UK? Not very readily.

CME's job anyone?

 

If the lessons of all the previous failed attempts from 1998 to present are not being learnt, it would seem that staff leaving and being replaced and, change of operators, results in knowledge/wisdom not being passed on so, history repeats itself.

I recall a few years ago that the BR Loads book had been abandoned, as the new private railway incumbents knew better.

This is a lack of communication problem, as are so many things in life these days. The locos/stock are a result of this, not the cause.

 

Footage from a couple of locations including Betws-y-Coed in the pouring rain and Abergele on a beautiful evening.

 

The last clip shows one person not just leaning out but wearing goggles, implying that he was doing a lot of it.

 

The extra wind resistance is prob why she came to grief!!

 

And?

 

What of it? If he managed to do it,good luck to him. On the other hand perhaps he was apprehended by the "droplight police" seconds later?!

Do we really have to go on and on about this?

 

Perhaps he was about to jump out and go for a swim.......