Lego Turning Radius compared to Real Life or G-Scale Models

[edsmith0075]

I am interested in figuring out what the sharpest radii are in real life locomotives and also G Scale modeling. I am planning to utilize ME Models wider turning radi tracks and am curious how they compare to real life limits or even G scale train modeling limits. I know the stock turning tracks by Lego are unreasonable when building functional accurate model trains.

Ultimately I am trying to get as close to O or G scale standards and quality. I want to show people that Lego Trains are legit modeling tools and not stuck at being viewed as a toy. I hope that makes sense.

Ed

[supertruper1988]

The biggest part of this is choosing a scale to work in. There are a few guys that build in 8 wide but that makes for some very expensive projects as they are all MOC builds. You should checkout railbricks.com. They have some good articles for building more realistic model trains.

[dr_spock]

Another thing to consider is the amount of space you have for the layout and how fast you plan to run your trains through the curves. Gentle curves in mainline railroads take huge amount of space. On other hand, subways and narrow gauge have very sharp curves in real life. Is there a particular prototype railroad you want to model after?

I remember a lot of good articles on curves and stuff in old copies of Model Railroader magazine.

[Duq]

I just googled around a bit and found it surprisingly hard to find any conclusive figures which is an answer in itself I guess...

The minimum radius varies, depending on the type of railway and the location/country.

Street track (trams) has very tight turns dictated by the requirement to fit in cities. As a result speeds are low and cars are short. High speed trains have extremely wide curves because their prime requirement is speed.

Other examples of tight turns are mountain railways and industrial lines.

So just pick your subject wisely and you'll be fine ;-)

https://en.wikipedia.org/wiki/Minimum_railway_curve_radius

[3D LEGO]

edsmith0075,

This may sound weird, but here is a suggestion to piggy back onto those already given. Pull up you world map of choice: Google Maps/Earth, Mapquest, Bing, etc and using the satellite view to compare different track geometries. Things to look at would be the area of interest you are pursuing. If industrial, then find industrial centers, rolling mills, etc. Or if you want mainlines crossing vast expanses or geographical features then look up those. Take screenshots and use the built in scale as your guide to see how things compare. Then choose the track geometry to match what it is you want to represent.

Looking at examples of rolling stock, a DB Class KÖF III | BR 353 (UIC: B) small shunting locomotives can fit in and around places undreamed of. A Siemens Vectron (UIC: Bo'Bo') is a mainline European freight locomotive though its Bo'Bo' configuration still allows it a fair amount of flexibility. But on the extreme scale, a historic ALCO 4000 class 4-8-8-4 (UIC:(2'D)D2'4h) "Big Boy", while articulated, needed straight running to operate and thus were confined to the mainline between Omaha, NB and Ogden, UT in the United States. (Today with much of the trackage across the county having improved greatly, it is very likely that UP Big Boy #4014 will be headed to places yet visited once restored.)

I hope that you are able to find what works for you. But ditto on the aforementioned comment about scale: that is something to consider as that can very well be a deal breaker when considering parts investment.

3D LEGO

[Q3671]

streetcar => R 30m, R 50m in the city

[greenmtvince]

NMRA has some recommended practices if you want to get close to prototypical.

http://nmra.org/sites/default/files/standards/sandrp/pdf/rp-11.pdf

If you want a point of comparison, R40 curves are: 12.5" radius and ME R104s are 32.5". I forget what PennLUG Grand Curves are. LEGO turnouts are roughly #2.

O-scale is 8-wide for North American Prototypes, 7-wide for European. S Scale is about 6-wide.

[CrispyBassist]

Based on the scale I use for my trains (1 stud = 1.3 feet) and a bit of railroad knowledge picked up through my grad school classes I can give you the following:

R40 (standard LEGO curves) = 52' radius

R104 (largest ME Models) = 134.5' radius

23° curve (sharpest that a standard diesel locomotive can operate through) = 250' radius

6° curve (generally sharpest mainline curve) = 955' radius

Judging from your Flickr I'm guessing you're going for mainline North American freight?

[edsmith0075]

Yep, American mainline. I guess the bottom line is what curve ratio or degree can I use with a more detailed lego train model thats 8 wide, stairs attatched to chasis ( not the bogie ) and will support coupling ( Kaydee couplers mod ). I am trying to figure this out and have been googling different scales. I am prepared to make a large investment in ME Models larger turning radii but want to make sure I order the most compatible.

Ed

BTW: Thank you to all who reply to my post. I love the reward of building trains with legos and I value the support from these boards!

[greenmtvince]

Even with the ME models curves, the switch tracks are still the limiting factor. So even if you can run on R104s, it's best to build models that can negotiate an R40 anyway.

That is, unless you plan to build your own large radius turnout.

[zephyr1934]

Yep, American mainline. I guess the bottom line is what curve ratio or degree can I use with a more detailed lego train model thats 8 wide, stairs attatched to chasis ( not the bogie ) and will support coupling ( Kaydee couplers mod ). I am trying to figure this out and have been googling different scales. I am prepared to make a large investment in ME Models larger turning radii but want to make sure I order the most compatible.

Ed

BTW: Thank you to all who reply to my post. I love the reward of building trains with legos and I value the support from these boards!

Probably the best thing you could do is buy a few Kaydee couplers and build up a couple of test cars to see what works. I've seen big boy MOC's that look good (on the straights) and can navigate standard lego curves (not so pretty). So it probably comes down to your own preferences. Oh, and even the traditional model railroaders run into this problem- different cars and locomotives are rated for different radii of curves.

Even with the ME models curves, the switch tracks are still the limiting factor. So even if you can run on R104s, it's best to build models that can negotiate an R40 anyway.

That is, unless you plan to build your own large radius turnout.

At least some of the old time lego train modelers (e.g., Dan Siskind and John Neil) built some nice looking steam engines in the days before BBB wheels. They would use large technic wheels or similar flangeless wheels to make the drivers and then have guide wheels inside the track. So their layouts had no switches on the mainline, relying strictly on the hand of ... for switching. I suppose you could also build a transfer table though. Actually, thinking about it further. Some of the earliest switches were stub turnouts and didn't have points, they actually physically moved the rails between different sets of tracks.

You could use a piece of flex track and a very long straight section to completely avoid the frog. Probably wouldn't be pretty, but it would allow you to switch without going custom built.

[someguy]

From looking at your flckr account I am curious as to where you would use the R104 curves? Speaking for myself, I would not order that large a radius curve if I only had that amount of space shown in the pictures. If I had a large open area where I could easily fit r 104 curves I would. Lego is certainly one of those things where you have to ask yourself if the expense is worth the fun you will have with it.

That said, I would see how fast your trains go and how far they can turn before you order new curves. If your trains can negotiate R40 curves at full speed and can turn on R40 then I would get R40.

I recently upgraded my lionel track from O27 to O52 (with banking) so I could drive my trains faster, and for me it is totally worth it.

[Brickthus]

The minimum radius on a British main line is 250ft. Tracks in yards go tighter; some used to be as tight as 40ft radius, accompanied by a notice saying "only 0-4-0 engines beyond this point" because an 0-6-0 would derail. A book of the railways of Burton-on-Trent showed this in a picture. This was when the town used to have tracks down the main streets for moving grain and coal wagons about for the breweries, before the widespread use of 44 tonne lorries!

I build as close as possible to 8mm:1ft scale, 1 stud to the foot.

For my large layouts I use 104ft on the main line and 72ft on auxiliary lines. 40ft is only allowed in sidings. My previous layout.

For small layouts with a selection of trains I use 72ft on the running lines and 40ft only in sidings. Small layout.

A grand curve (of straights) would be nice for the main lines, and close to the 250ft minimum, but most of my trains are able to sustain adequate speed for exhibition running on 104ft curves. I haven't yet splashed out on ME track so I have 2 straights between each curve on the main lines and 1 straight between curves on other lines. This means oscillation is possible, though the longer bogie centre distance means the Pendolino works well with a 104ft curve.

I have also modelled flexi-track to 72ft and 104ft curves, with ballast, slope and cant.

All these things depend on the compromises of scale and selective compression. The key is to pick a set of them that fits together well - scale size, train length, vehicle dimensions, curve radius, power solution, running speed.

A tighter constraint for non-flat LEGO layouts is that the maximum slope on a model railway of any scale (except rack railways) should be 1 in 30. That's 1 plate for every 12 studs long! This is the same constraint used by other model railways.

It is also said that the difference between a train set and a model railway is the signalling, but this may be alleviated as more real railways move to ERTMS cab signalling.

For scale I have settled on getting better than 'OO' gauge scaling (which is quite poor but accepted in the model railway fraternity) and as good as other model railways for prototypical operation. It is more important to have something running on your layout for the public to see than the number of rivets; we're not trying to make 'P8'!

Mark

[zephyr1934]

From looking at your flckr account I am curious as to where you would use the R104 curves? Speaking for myself, I would not order that large a radius curve if I only had that amount of space shown in the pictures. If I had a large open area where I could easily fit r 104 curves I would. Lego is certainly one of those things where you have to ask yourself if the expense is worth the fun you will have with it.

That said, I would see how fast your trains go and how far they can turn before you order new curves. If your trains can negotiate R40 curves at full speed and can turn on R40 then I would get R40.

I recently upgraded my lionel track from O27 to O52 (with banking) so I could drive my trains faster, and for me it is totally worth it.

At least based on the kickstarter numbers I think the R104 were the most popular, quickly followed by the R56. Which makes sense, there are a lot of people who want as wide as possible and there are a lot of people who just want another 16 studs beyond R40, presumably for double track in somewhat tight spaced. Even if you do not have room for the full large radii curves, by introducing small changes of direction the R104 make the straightaways more interesting then simply straight track.

Taking a slightly different view from someguy, I'd suggest designing as many of your trains as possible to negotiate R40 curves in case they have to, but if you prefer the look of wider radius curves, by all means do so. After all, it is most important that you like the look of your creation.

[Daedalus304]

I agree with Zephyr, design your trains to work with R40 even if most of your layout is going to be using a bigger radius. Right now, no matter how many r104 or r88 curves you have going, at the end of the day you're going to have to deal with using LEGO's switches (Unless you're venturing into custom-building your own, of course), and those are R40 s-curves.

I would say that you shouldn't worry too much about the radius of your curves when it comes to trying to get LEGO trains to seem like a legitimate hobby. I did a presentation to the New Mexico model railroaders earlier this year on LEGO model railroading, and they didn't seem to think the tight turns made the hobby any less 'legit'; if anything they were really impressed that so many LEGO train builders could build such good looking engines that still took such absurd turns. Ultimately what wins train hobbyists over is the details; if your locomotives, rolling stock, and landscaping look great you're a good deal of the way there. Getting working signals and yard maneuvers that don't require "the hand of god" is the next big thing after that.