John's Jottings

154. Weighty Problems - April 2019

Posted on March 31, 2019 at 5:35 AM

There was a real expert on one of the layouts at the Salchester exhibition. He would explain to all and sundry why only certain engines were allowed to go along the lightly-laid branch line or enter the even lighter-laid lines in goods yards. He explained in great detail the GWR’s system for categorising the weight restrictions for their routes and how cab-side symbols were used to indicate the route availabilities of each of their locomotives. This was reflected in the livery details he applied to each of his models. “We modellers must have prototype accuracy,” he said many times.

What he didn’t seem to realise was this true-to-prototype policy didn’t apply to his wagons. The contents of mineral wagons ranged from three-quarters empty to one-and-a-quarter full. The top lumps were precariously hanging on to their position, instead of rolling down the heap and falling off the wagon altogether. Was it prototype practice for some collieries to use glue to keep their loads in place?

Another freight train included several wagons with four coils of steel strip just fitting nicely onto each wagon. But their combined weight far exceeded the carrying capacity of the wagon. Now if only real railway wagons with equivalent strength could be assembled from plastic kits, just think how few wagons our rail companies would need to provide.

On the same layout there was a Plate wagon, with four pieces of thick grey plastic sheet aboard. In real life, if they had been steel, the wagon springs would have cracked and the entire chassis pan-caked onto the rails. But the wheel-loading would have also have exceeded the strength of the rails, so no doubt buckled and shattered track would have been added to the mess!

At the same show we heard of an HGV delivering two drums of 750-volt cable to a trackside depot. Now each drum was about 7ft in diameter and weighed over 12 tonnes. That was greater than the tail lift could carry. The lorry driver called for a crane.

“We don’t have a crane, either fixed or mobile,” the yard foreman replied.

“What do you have?” the delivery driver asked.

“We’ve a fork-lift truck. You could use that.” Examination showed it to have a capacity of only 1.5 tonnes. The foreman rang a superior to get advice.

“Open the tail-gate and roll them out,” was the received wisdom.

“Once a drum starts rolling, how are you going to stop it?” the driver asked incredulously. “You lot won’t want to stand anywhere near where it’s going to fall off the back end, will you?” None of the yard workers would be that stupid, would they? “You’ll be chasing after it, but it’ll only stop when it mounts a track and falls over. You could so easily block a running line.” The workers hadn’t thought of that either.

“We could set out some sleepers across it path and stop it that way,” they suggested

“What’s more likely to happen,” the driver told them, “is that when the cheeks of the drum hit the ground, the weight of the cable will wrench the core free. You’ll then be left with a shattered drum and a potentially fractured cable. There’s no way you’ll be able to extract the cable or move it to site.

Eventually the foreman conceded that they couldn’t unload it. He made arrangements for that to happen at another depot – one with a suitable crane. The road driver was annoyed at the extra time this all took.

“It just goes to show that the model operators hadn’t really understood about the rules that every company had for loading wagons,” our chairman commented. “Make sure we don’t make the same mistakes on our layouts.” We all agreed, but we’ll just have to see what actually happens.


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