LoneBrickerSG Posted February 13, 2015 Posted February 13, 2015 Hello This is directed mostly at a lot of the guys who have MOC'ed steam locomotives. Steam engines are a new tangent of lego trains for me. I am a fan of large steam. I like 'Northerns' (4-8-4 wheel arrangement) most, but many others also. There is one type of Northern that I know of, but I don't see modeled in Lego. I would like to build one for myself, and have already started gathering wheels and specific detail parts for it. I'm not too used to the mechanics yet, though. I think the chassis and running gear will be the hardest part for me. Does anyone have any helpful resources they can point out to me? Are there MOC guides available for steam locos? This is the type in question, a Russian P36 type. Like most Soviet-engineered steam engines, it has a smaller drive wheel diameter than its American counterparts, and that's something I want to take into consideration when building one. If I go with smaller driver wheels available from BBB, does that complicate the design or are they as easy to integrate as the official Lego ones? Quote
jtlan Posted February 13, 2015 Posted February 13, 2015 I'll address your questions in reverse order. This is the type in question, a Russian P36 type. <snip (image)> Like most Soviet-engineered steam engines, it has a smaller drive wheel diameter than its American counterparts, and that's something I want to take into consideration when building one. If I go with smaller driver wheels available from BBB, does that complicate the design or are they as easy to integrate as the official Lego ones? The official Lego drive wheels are the same size as the BBB "L" drivers, with a few differences: - BBB wheels come in more colors - Official Lego wheels have a counterweight and more spokes - Official Lego wheels have a groove for a tire (rubber band) However, you might not want to use these wheels; see below. I'm not too used to the mechanics yet, though. I think the chassis and running gear will be the hardest part for me. Does anyone have any helpful resources they can point out to me? Are there MOC guides available for steam locos? I'll describe what I usually do: In most cases, I start by finding an engineering drawing of the locomotive. Here's one for the P36: Full size at Wikipedia. The engineering drawing helps show what the locomotive really looks like, which can often be distorted by photos. You might also want to pick a scale to model at. This is actually more detailed than just saying "6/7/8-wide"; In my case, I usually model at 15 inches / stud (~155 mm / plate). If you pick a scale, you can put a scaled version of the drawing in front of Lego graph paper to help you figure out how large various parts of the locomotive should be. In this case, at the scale I use, the P36 is ~8 studs wide. This isn't too surprising -- Russia has a gigantic loading gauge and its locomotives are often huge. However, at this scale the 1850mm-diameter drivers should be about 38mm in diameter -- closer to the size of the BBB "XL" drivers! After figuring out roughly how far apart everything should be, I make a skeleton of the chassis. This allows me to test the running characteristics of the locomotive before starting work on anything else -- if the chassis doesn't work, there's not much point to anything else. Usually, all the drivers will be mounted to a single rigid frame, and the front and rear trucks will pivot off of this frame. The pistons and running gear are also usually attached to this rigid frame if you have working driving rods (rather than just connecting rods). It's also important to consider how the locomotive's body will attach to the chassis. On shorter locomotives, you can simply attach the body to the rigid frame containing the drivers. However, on longer locomotives, doing this will result in gigantic amounts of overhang on curves. Instead, you often have to attach the body with rotating (and sometimes sliding) joints to various positions on the chassis. What's best in this case strongly depends on the actual locomotive you're modelling, and finding the correct pivot points requires trial, error, and practice. Quote
LoneBrickerSG Posted February 13, 2015 Author Posted February 13, 2015 (edited) You might also want to pick a scale to model at. This is actually more detailed than just saying "6/7/8-wide"; In my case, I usually model at 15 inches / stud (~155 mm / plate). If you pick a scale, you can put a scaled version of the drawing in front of Lego graph paper to help you figure out how large various parts of the locomotive should be. In this case, at the scale I use, the P36 is ~8 studs wide. This isn't too surprising -- Russia has a gigantic loading gauge and its locomotives are often huge. However, at this scale the 1850mm-diameter drivers should be about 38mm in diameter -- closer to the size of the BBB "XL" drivers! Holy buckets. I was hoping to not exceed the 'L'-size drivers on this. Unlike American Northerns like #4449, UP #844 or Milwaukee Road #261, the P36 design has quite a bit of empty space between the boiler and drive wheels, something that the Russians did with many of their locos for ease of maintenance wherever they didn't have cranes large enough to lift engines. I was thinking that sticking with slightly smaller drivers would help keep this appearance, and hopefully make the wheels look proportionally correct compared to other locos of similar size. After figuring out roughly how far apart everything should be, I make a skeleton of the chassis. This allows me to test the running characteristics of the locomotive before starting work on anything else -- if the chassis doesn't work, there's not much point to anything else. Usually, all the drivers will be mounted to a single rigid frame, and the front and rear trucks will pivot off of this frame. The pistons and running gear are also usually attached to this rigid frame if you have working driving rods (rather than just connecting rods). Do you do this in a virtual program first, or do you make a test piece with physical parts? It's also important to consider how the locomotive's body will attach to the chassis. On shorter locomotives, you can simply attach the body to the rigid frame containing the drivers. However, on longer locomotives, doing this will result in gigantic amounts of overhang on curves. Instead, you often have to attach the body with rotating (and sometimes sliding) joints to various positions on the chassis. What's best in this case strongly depends on the actual locomotive you're modelling, and finding the correct pivot points requires trial, error, and practice. I figured this part would be the most difficult. I know that the realistic steam engines that I see are indeed labors of love and take a lot of nitpicking to get right. If it were any other way, I wouldn't consider it model railroading. Thank you jtlan, your answer has the technical aspects that I was hoping to get advice on. The advance planning tip using graphs and figuring a scale is extremely helpful. Edited February 14, 2015 by LoneBrickerSG Quote
Duq Posted February 14, 2015 Posted February 14, 2015 Have a look at the Flickr Train MOCs group: https://www.flickr.com/groups/legotrains/pool The Flickr Train Ideas group: https://www.flickr.com/groups/legotrainideas/pool And Railbricks: http://railbricks.com/instructions/steam-locomotives/ I would especially recommend the instructions for Ben's BR023. Quote
jtlan Posted February 14, 2015 Posted February 14, 2015 Holy buckets. I was hoping to not exceed the 'L'-size drivers on this. Unlike American Northerns like #4449, UP #844 or Milwaukee Road #261, the P36 design has quite a bit of empty space between the boiler and drive wheels, something that the Russians did with many of their locos for ease of maintenance wherever they didn't have cranes large enough to lift engines. I was thinking that sticking with slightly smaller drivers would help keep this appearance, and hopefully make the wheels look proportionally correct compared to other locos of similar size. Picking wheel size is tricky. The flange on Lego train wheels is a significantly larger proportion of the wheel's diameter than is the case for their real-world counterparts. In addition, the range of available sizes is limited. Generally, I consider a wheel suitable for use if the scaled diameter is between the hub and flange diameters of the model wheel. Alternatively, you can adjust your scale until the wheel size feels "right". <snip (re: chassis testing)> Do you do this in a virtual program first, or do you make a test piece with physical parts? Chassis testing basically has to be done with physical parts. The collision-detection algorithms of CAD programs are either suspect (LDD) or nonexistent (everyone else). In addition, some problems will only manifest on real models -- sagging beams, wheels slightly smaller than their quoted size, etc. You'll be using the wheels eventually, so no real harm in ordering them early, right? Quote
LoneBrickerSG Posted February 14, 2015 Author Posted February 14, 2015 Chassis testing basically has to be done with physical parts. The collision-detection algorithms of CAD programs are either suspect (LDD) or nonexistent (everyone else). In addition, some problems will only manifest on real models -- sagging beams, wheels slightly smaller than their quoted size, etc. You'll be using the wheels eventually, so no real harm in ordering them early, right? I suppose not. If I don't use red wheels on a loco, I can always put them in a 'scrap pile'. Quote
ecmo47 Posted February 14, 2015 Posted February 14, 2015 http://www.ebay.com/itm/LEGO-Steam-Locomotive-2-8-2-w-Oil-Tender-UNION-PACIFIC-Built-fully-tested-Train-/131429416509?pt=LH_DefaultDomain_0&hash=item1e99cdbe3d Here is a steam locomotive for sale. (No, it's not mine). It is a nice example of what can be done with Lego. Quote
SavaTheAggie Posted February 14, 2015 Posted February 14, 2015 I wish I hadn't clicked that eBay link. Both locomotives that seller has listed are my design. --Tony Quote
LoneBrickerSG Posted February 15, 2015 Author Posted February 15, 2015 (edited) http://www.ebay.com/...=item1e99cdbe3d Here is a steam locomotive for sale. (No, it's not mine). It is a nice example of what can be done with Lego. I was thinking about this too. I know there's instructions for #4449 somewhere. I would honestly consider buying those just to learn from the chassis. Actually that would just be poetic justice, since #4449 was the one that made me love 4-8-4 steam engines in the first place! Edited February 15, 2015 by LoneBrickerSG Quote
MusicaRibelle Posted February 15, 2015 Posted February 15, 2015 Hmm.. yes, Sava, when I clicked on the link I thought it looked like one I had seen before... Well, at least he's not selling just the instructions -- that would be worse. Quote
LoneBrickerSG Posted February 15, 2015 Author Posted February 15, 2015 (edited) Well, at least he's not selling just the instructions -- that would be worse. There is this. I love Sava's work, but maybe the guy is bored with it and just wants to offload the model? Who knows. It's not much different from a scale model railroader selling a loco he has kitbashed extensively. If the guy were selling Sava instructions then that's definitely a problem. Edited February 15, 2015 by LoneBrickerSG Quote
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