North East model railway – Matters Arising 4

Continuing to discuss the points brought up on the video comments on the YouTube channel, I have expanded the explanations in this blog because it is not always possible to adequately answer the questions in the  limited comments space.

Long Trains

One of the design requirements for Trenholme Junction was 'the trains must be of prototypical length'.

Quite a short sentence, but hidden in there are quite a few other considerations to take into account. 

The  recent (last 10 years) crop of super quality locomotives has meant that we can now run trains of a length we could only dream about before that. I'm talking here about locomotives in the UK, in America their market has had this capability for a long time. The American influence on this section of the hobby is very good for us here in the UK. 

The videos below show a couple of examples of long trains. To see the Channel, the link is at the bottom of this page.

Tests on my layout have have been truly amazing, one Hornby Stanier 2-8-0 locomotive pulled ninety Bachmann mineral wagons. You only have to marvel at this when you grip the coupling on the first wagon and pull it yourself, the weight involved is really surprising.

Track

'....it amazes me the amount of wagons and or coaches propelled over double crossovers with no derailments....' is a quotation from a recent video comment.

There are quite a few things in response to this, one is of course the boring but absolutely vital subject of track laying. You really need to make sure that the points are laid absolutely flat and the approach tracks are not under any stress. Stress, where the connected tracks are not in line will distort the turnout and unpredictable running will be the result. Neglect in this area may not be too much of a problem if you run very short trains, but once you multiply the numbers by ten or fifteen the problems are amplified accordingly.

The second and equally important point on the subject of track laying is the selection of the type of points (switches) you use. On Trenholme Junction two sizes of points were selected. Large and Medium. Ideally, Large radius points should be used wherever possible, but practical considerations forces compromises. Most of the points on the passenger carrying main lines and the major junctions all use large radius components. All the remaining points are medium radius. I dwell on this subject of the size of the points I used because smooth running, if you wish to perform complicated movements with lots of rolling stock, is determined by this selection.

On small layouts it is usual to use setrack components because the space available. These components perform well on a limited space layout, but the diverging track geometry is pretty severe and are not affected by long trains.

Couplings

There are many different sizes and types of couplings in OO gauge but most are variations on Triang's 'Tension Lock'. Its a good thing that most manufacturers rolling stock can be easily coupled together but on long trains they can and do cause problems. On Trenholme Junction the long mineral trains of fifty or so wagons are all Bachmann and they run very well, with one point to note. It is important to make sure the couplings have hooks on both wagons especially if the wagon is at the front of the train. If the hook is missing from one wagon, it will twist as it runs and is prone to derailment.Trains of mixed manufacturers' couplings are a little more unpredictable, generally I find probably ninety percent are fine but the longer the train the more prone to misbehaviour where mixed types are at the front of the train.

Speed

The final part in this piece is to deal with speed. It is surprising how many layouts I look at and have to cringe at the speed the trains travel around the layouts. Its not easy to get the speed right but you can make some rough comparisons by sitting next to a real railway and just count how many seconds it takes a train to pass you by. Take a note of the number of vehicles in the train and then do they same thing on your model with a similar length train. Most surprising.

The already mentioned super locomotives together with DCC control make speed control an easy thing to achieve.

To say there are no derailments on my layout is of course untrue but aren't many, most are caused by trying to run over points set against the train or by a fault which shuts the power off to the track abruptly, fast moving trains and those on curves being particularly vulnerable.

In conclusion, correct track selection, track laying and appropriate speed will allow the model railway to behave in the same way as the prototype.

To view the channel, follow the link below
http://www.youtube.com/user/dougattrenholmebar