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| PRR S2 https://www.rypn.org/forums/viewtopic.php?f=1&t=24038 |
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| Author: | bobyar2001 [ Wed Oct 03, 2007 11:43 pm ] |
| Post subject: | PRR S2 |
Builders photo of this unusual and short lived locomotive, which worked better for Lionel than the PRR: http://abpr2.railfan.net/abprphoto.cgi? ... 6200_C.jpg |
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| Author: | Dave Lewandoski [ Thu Oct 04, 2007 5:30 am ] |
| Post subject: | Re: PRR S2 |
looks powerful. thanks for sharing |
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| Author: | rob216 [ Thu Oct 04, 2007 10:30 am ] |
| Post subject: | Re: PRR S2 |
I have always wondered as to why this engine didn't work out. What caused not to be successful? |
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| Author: | survivingworldsteam [ Thu Oct 04, 2007 10:55 am ] |
| Post subject: | Re: PRR S2 |
rob216 wrote: I have always wondered as to why this engine didn't work out. What caused not to be successful?
Most steam turbine locomotives consumed large amounts of steam at slow speeds. They also required a seperate turbine for backing up, and gearing. This made them way more complicated than it was worth in terms of higher pressure or fuel saving. The only ones that were moderately successfull were a group of condensing engines built in Sweden. One was even tried in Britian. |
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| Author: | whodom [ Thu Oct 04, 2007 2:12 pm ] |
| Post subject: | Re: PRR S2 |
James is correct about the major problems with the S2. Basically a steam turbine can be designed for optimum performance at only one rotational speed. The steam blows into the turbine through multiple nozzles and strikes a series of alternating stationary and moving blades. The shapes and angles of these blades are carefully calculated in order for the maximum energy to be extracted from the steam. If the moving blades are moving too fast or too slow, much of the efficiency is lost. The S2 was very efficient when cruising along at typical passenger train speeds, but at low speeds and especially when starting, it was a different story. I've read that in the case of the S2, there was almost no resistance to steam flow when the engine was starting. As a result, the boiler pressure would rapidly fall, stressing the boiler and causing a high number of staybolt failures. As you can imagine, efficiency was pretty miserable during these conditions too. The most successful Swedish engines actually weren't condensing. See this page (these engines are located on the lower half of the page) for more info: http://www.dself.dsl.pipex.com/MUSEUM/L ... edturb.htm My guess is that the Swedish turbine engines were designed for relatively slow speed operation and their turbines were geared appropriately, so that they spent most of their time operating in their most efficient speed range. Two of these engines have been preserved. |
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