JohnBS Posted June 5, 2013 Share Posted June 5, 2013 Hi folks, A new thread. Someone asked me the other day how heavy the Saint 3-D printed loco and chassis would be - presumably a concern over haulage capacity. This get me thinking and gave me the incentive to do something I had intended for ages - get some portable digital scales. A couple of days later they arrived. You can guess what's coming - the geek in me couldn't resist weighing all my locos (these are all for 2mm GWR steam outline locos, gross weights include tenders where appropriate). The the top three results were not too surprising 1 4083 Abbotsbury Castle 4-6-0 - modified Peco Jubilee with tender mechanism and traction tyres 120g 2 4706 47xx class 2-8-0 - scratch built, tender-mounted motor 118g 3 6005 King George II 4-6-0 - modified Farish King 107g Number 4 was a slight surprise but I had squeezed in as much back-end weight as possible, and a bearing tender 4 E430 Southern L12 class 4-4-0 - modified Farish Midland compound 97g 5 4918 Dartington Hall 4-6-0 - modified Farish Hall 96g 6 3376 River Plym 4-4-0 - scratch built, tender-mounted motor 95g Then came a couple more modified or scratchbuilt locos, followed by the first proprietary 'straight out the box' entry 9 2892 2884 class 2-8-0 - Dapol, mechanically unchanged 85g There followed a group of mainly unmodified proprietary locos and bringing up the rear of the tender locomotives were the following 18 9304 Mogul 2-6-0 - modified Farish 61xx with tender 70g 19 2857 28xx class 2-8-0 - modified Farish 4F 69g Then close behind came the tank engines - the second one was a slight surprise as it is the smallest of all, but is mainly built of copper-tungsten! 20 4536 45xx class 2-6-2T - scratchbuilt 67g 21 1435 517 class 0-4-2T - scratchbuilt 61g These were followed by a group of modified Farish locos and the tail-end charlies were a couple of unmodified locos 29 1425 14xx class 0-4-2T - Dapol 39g 30 9659 Pannier 0-6-0T - Dapol 32g It is clear from operating the locos under exhibition conditions that haulage capacity is not simply proportional to gross weight; variables include tenders, bogie and pony contributions and of course, traction tyres on some of the proprietary mechanisms, but current collection is also significantly improved by increased weight. I don't have any diesel/electric locos (other than a diesel railcar, 80g) but would anticipate that they would be considerably heavier. John Link to post Share on other sites More sharing options...
richbrummitt Posted June 6, 2013 Share Posted June 6, 2013 I must buy some digital scales. SWMBO would like some and now I have an excuse to get on with it. Link to post Share on other sites More sharing options...
JohnBS Posted June 6, 2013 Author Share Posted June 6, 2013 I must buy some digital scales. SWMBO would like some and now I have an excuse to get on with it. Rich,The ones that I got are described as 'pocket digital scales' on-line and were 8.99GBP plus 2.00 p&p. Their capacity is up to 1000g in 0.1g units. John Link to post Share on other sites More sharing options...
34theletterbetweenB&D Posted June 6, 2013 Share Posted June 6, 2013 ...It is clear from operating the locos under exhibition conditions that haulage capacity is not simply proportional to gross weight; variables include tenders, bogie and pony contributions and of course, traction tyres on some of the proprietary mechanisms, but current collection is also significantly improved by increased weight.... The basic data required is the weight applied to the driven wheels, and whether any of these have traction tyres. There is some variability in adhesion from metal tyres too...(Determines how much force the mechanism can exert on the rail, typically the motor capability exceeds the available adhesion so that isn't the limiting factor) Then you need to know the drag from all other wheels on the complete loco: that is removed directly from the force the driven wheels can exert, leaving whatever is left over for hauling a train. Link to post Share on other sites More sharing options...
Miss Prism Posted June 6, 2013 Share Posted June 6, 2013 Some out of the box examples, inclusive of tenders: 08 46g WD 72g A3 86g Terrier 30g Std 4 tank 74g Std 3 tank 54g Std 4 Mogul 70g Q1 58g M7 26g 9F 84g Britannia 96g Link to post Share on other sites More sharing options...
RMweb Premium Izzy Posted July 2, 2013 RMweb Premium Share Posted July 2, 2013 I'll add some diesel weights for comparison. First some Farish, these all have wheels to 2FS, 03/04 - 32gms - wheels Farish machined. 08 - 44gms - wheels Farish machined. 20 - 56gms - 2mm SA drop-in 24 - 70gms - 2mm SA drop-in and a couple with standard Farish N gauge wheels, yet to be converted. 37 - 91gms 47 - 94gms Farish DMU's, again 2FS, all using 2mm SA drop-in wheels. 101 - 59gms 108 - 61gms trailers - 24gms Dapol. all wheels 2FS, machined Dapol 66 - 71gms 86 - 76gms 156 - 69gms trailer - 35gms The reason I detail the wheels is that they can make a weight difference, even though this may not impact on the haulage capability. 2mm SA drop-in sets or machined wheels being lighter than original ones. Generally, haulage capability seems related to overall weight. Izzy Link to post Share on other sites More sharing options...
JohnBS Posted July 2, 2013 Author Share Posted July 2, 2013 Izzy, I'm surprised that the diesels weren't heavier, though of course most will have the advantage of all axles being driven, not having ponies, bogies or tenders to drag around for the ride. John Link to post Share on other sites More sharing options...
RMweb Premium Izzy Posted July 3, 2013 RMweb Premium Share Posted July 3, 2013 Izzy, I'm surprised that the diesels weren't heavier, though of course most will have the advantage of all axles being driven, not having ponies, bogies or tenders to drag around for the ride. John Hi John, I thought you might be a bit surprised, and especially after seeing the weight of some of your steam locos and your comments. The advantage is in not having to drag anything unproductive along for the ride, but although the basic tenent of more weight equals better haulage generally holds true, weight distribution still seems important in some respects as it does with steam locos. For example although most tests were carried out on the flat, on my small circular layout, I did try a few using a circular test track on a sheet of hardboard so I could angle it for incline purposes. This threw up the odd difference. For example the Farish DMU's, despite only having one bogie driven, could cope with almost any incline, yet the slightest rise caused the Dapol DMU to sit and spin it's wheels although it's got all axle drive. From the basic tests I have carried out it seems it's quite difficult to easily quantify what any loco will haul because a lot depends on the running qualities of the stock as well as their weight, which can seem to vary quite a bit. Izzy Link to post Share on other sites More sharing options...
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