Curve radius limits for different trains?

[gavino200]

Does anyone know a good source for information about what trains require what minimum radii? There doesn't seem to be a thread dedicated to this. @katoftwmentioned in another thread that Shinkansens need 315mm or larger. Is there agreement about that? What about larger steam engines? Other locos or wagons that have special requirements?

 

 

 

[Yavaris Forge]

I guess it really depends on what radius you want to build on your layout. My impression so far was that 'all' mainstream JP stuff (excluding Shinkansen) runs at least on 249mm radius. I can give you a list of my fleet that runs on 222mm without it being specified anywhere, although my fleet isn't as large as some others around here.

 

Doing a bit of research I found this site with at least some models listed. 

 

Here is another site with a small list down below. This site also states that a Tomix E7系 can manage R243, can anyone confirm?

Edited March 21, 2022 by Yavaris Forge

[cteno4]

I guess there is also a distinction between “can run well on” and “can run well on with a more complicated layout”. Lots of times folks test this on a loop of what ever radius track and say it works, but throw in points, crossovers and other s curves and such and it may not run well on the tighter radiuses.

 

our first JRM layout we had a few different arrangements of our inner loop which had a tighter space and thus smaller radiuses, but tired to do interesting layouts there along with #4 points for space. While they I don’t think used anything below r282, it worked, but not all trains were happy there, especially with shunting, but we never tuned #4 points, was easier to just run trains that were happy on it.

 

jeff

[gavino200]

3 hours ago, Yavaris Forge said:

I guess it really depends on what radius you want to build on your layout. My impression so far was that 'all' mainstream JP stuff (excluding Shinkansen) runs at least on 249mm radius. I can give you a list of my fleet that runs on 222mm without it being specified anywhere, although my fleet isn't as large as some others around here.

 

Doing a bit of research I found this site with at least some models listed. 

 

Here is another site with a small list down below. This site also states that a Tomix E7系 can manage R243, can anyone confirm?

 

 

Thanks. It'll take me a while to parse that stuff. I'm guessing that the Tomix track names are just c-for-curve and the radius.

 

I wonder about some of the values given. They say that shinkansens should be ok with C243. That's almost the same as the Kato 249 that you mention. But your specifically exclude Shinkansens from this radius. Hmm. 🤔

 

 

Edited March 21, 2022 by gavino200

[gavino200]

1 hour ago, cteno4 said:

I guess there is also a distinction between “can run well on” and “can run well on with a more complicated layout”. Lots of times folks test this on a loop of what ever radius track and say it works, but throw in points, crossovers and other s curves and such and it may not run well on the tighter radiuses.

 

Totally, that's really important.

 

 

1 hour ago, cteno4 said:

 

our first JRM layout we had a few different arrangements of our inner loop which had a tighter space and thus smaller radiuses, but tired to do interesting layouts there along with #4 points for space. While they I don’t think used anything below r282, it worked, but not all trains were happy there, especially with shunting, but we never tuned #4 points, was easier to just run trains that were happy on it.

 

jeff

 

I ran into this problem two layouts ago. I had some complex turns in the center that were two tight to run larger steam trains on. We still refer to any track that too tight a radius to run everything well on as "Steambads".

 

Large radii really make complexity difficult. I may end up having only my larger loop be suitable for everything and using some smaller radii on my "city/commuter train" track. The trams can hack some really tight corners. I want to be able have at least part of the layout that can run pretty much any train that I can buy.

 

But I'd like to establish some reliable thresholds.

Eg.

Shinkansens need > Xmm

"Regular"trains need > Xmm

And any other exceptions.

 

BTW, when you say "shunting" do you mean "going backwards" or something more, like weaving in and out of yard lines?

[Kamome]

I don’t think it excludes all shinkansens although in recent years, Kato have started adding minimum radius information to a lot of their models. I don’t think the older models had this but used bogie mounted rapido couplers and had no diaphragm detail etc..

 

Certainly those with lower skirting around the bogies or with longer noses will have turning and clearance issues on certain track radius and configurations. 

[bill937ca]

Old models with big motors probably made minimum radius  a moot point.  Many an old Kato streamer was over scale because of the size of the motors.

 

[katoftw]

8 hours ago, gavino200 said:

But I'd like to establish some reliable thresholds.

Eg.

Shinkansens need > Xmm

"Regular"trains need > Xmm

And any other exceptions.

Any reason why you cannot use the minimum radi set by the manufacturers?

 

Every Kato model comes with instruction sheet with minimum radi needed.

 

Tomix I am unsure of, but think it is on their website for each model.

 

Hobby search also translate the manufacturer text of trains info. So you can check minimum radis there also.

Edited March 22, 2022 by katoftw

[Englehart]

^^ the locomotives seems to limit at C243 of those middle trolley

 

but for realism i find the C465 C541 closer to real life curve 😅

[Arctic]

For Kato models, looking at the Kato catalogue the rule is basically:

Shinkansen: 315mm

Everything else : 249mm

[katoftw]

9 minutes ago, Arctic said:

For Kato models, looking at the Kato catalogue the rule is basically:

Shinkansen: 315mm

Everything else : 249mm

Generally yes.  Like 99.99%.  Easy basic rule to follow.  Keeps it simple.

 

The is a few models that differ.  C11 for example is listed as R216 as a minimum.

 

---

 

Tomix like to say C280 minimum for their Shinkansens, but I find them struggling on C280.  C317 or R315 tend for better running.  Much like Jeff earlier mention of what really runs well at minimum radi.

 

Also Tomix's models, if you fit close couplers, many need to run at some step higher than their minimum listed radi.

Edited March 22, 2022 by katoftw

[Englehart]

^^ 

that's true it seems fitting it with TN limits it to 280 (non shinkansens) without extending it's shanks

[Rod.H]

5 hours ago, Arctic said:

For Kato models, looking at the Kato catalogue the rule is basically:

Shinkansen: 315mm

Everything else : 249mm

 

I think I saw some steam engines in the recent book that had 340mm minimums

[katoftw]

5 hours ago, Rod.H said:

 

I think I saw some steam engines in the recent book that had 340mm minimums

Probably HO.  There are a few N scale that require C280/R282 that are long and have extra drive wheels.

[bill937ca]

This is my source for old Kato steam engines being over scale.

 

http://www5a.biglobe.ne.jp/~toyoyasu/kcat_1.htm

 

http://www5a.biglobe.ne.jp/~toyoyasu/index.htm

Edited August 4 by bill937ca

[gavino200]

19 hours ago, katoftw said:

Any reason why you cannot use the minimum radi set by the manufacturers?

 

Every Kato model comes with instruction sheet with minimum radi needed.

 

Well, because it's not very clear what they are. The single folded sheet, four page leaflet that comes with shinkansens, has a box with two diagrams showing a right and a wrong way of doing something related to a R315-45 curve. Having this curve going directly to an x'd out track without a small intercalated track is wrong. With the small track all is ok. I don't know Japanese and can't interpret this. I'm guessing you know the answer. Would you be able to share it?

 

What is the minimum radius for a Shinkansen? Is that a minimum radius for running the shinkansen at full scale prototypical speed? Or is it a minimum to run at any speed. Is there a radius at which you can run a Shinkansen at a low speed but not at a high speed?

 

19 hours ago, katoftw said:

Tomix I am unsure of, but think it is on their website for each model.

 

I'll take a look. Thanks.

 

 

19 hours ago, katoftw said:

 

Hobby search also translate the manufacturer text of trains info. So you can check minimum radis there also.

 

I don't see it. Can you show me? https://www.1999.co.jp/eng/10803615

[gavino200]

I dug out some 315 track. That does seem about right. I know for sure that shinkansens and steamers can't run on R282.

 

It's actually a tighter curve than I expected. I wonder if that's fully reliable for all trains. Anyone know of a train, shinkansen or otherwise that can't handle R315 track?

[gavino200]

12 hours ago, Arctic said:

For Kato models, looking at the Kato catalogue the rule is basically:

Shinkansen: 315mm

Everything else : 249mm

 

Thanks. I'll go with this unless anyone tells me they've had trouble with either of these thresholds.

[gavino200]

7 hours ago, Rod.H said:

 

I think I saw some steam engines in the recent book that had 340mm minimums

 

Thanks. That helped me find where they list the specific loco radius in the catalog. I don't see a 340mm for any of the Japanese steamers. However the US Morning Daylight and Union Pacific Excursion trains are listed for R315, just like shinkansens.

 

The Euro high speed trains are a mixed bag.

Thalys R192

Eurostar R249

Class 800 R282

ICE4 R282

[disturbman]

Rivet counter mode on: The Class 800 is not an HST, even if its max speed is 230 kph.

 

Honestly, you should stick with 315 as a minimum. It's not too large and everything with TN drive on it with no problem.

Edited March 22, 2022 by disturbman

[gavino200]

Just now, disturbman said:

Rivet counter mode on: The Class 800 is not an HST.

 

Lol.

 

 

Just now, disturbman said:

 

Honestly, you should stick with 315 as a minimum. It's not too large and everything with TN drive on it with no problem.

 

I agree!! Although, I hope I never develop that coupler obsession that y'all have. 🤣

[disturbman]

It's not a coupler obsession, it's a gap obsession 😉 

[katoftw]

9 hours ago, gavino200 said:

 

I don't see it. Can you show me? https://www.1999.co.jp/eng/10803615

I don't see it either.

 

But the same train but 4 car set has radi text.

https://www.1999.co.jp/eng/10803602

Edited March 23, 2022 by katoftw

[bill937ca]

Another factor on minimum radius is the length of the cars. Most JR trains have 20m cars.  But some of the private railways like Keikyu and Meitetsu use 18m. I could run my Kato Keikyu Type 2100 Standard Set on R243 (Tomix) with no problems.  But the listing does not tell you that anywhere. You need prototype knowledge.

 

https://www.1999.co.jp/eng/10346807

 

The sharper your radius the greater your overhang on curves like in the case of 80 foot North American double stack container cars.

[katoftw]

8 hours ago, bill937ca said:

But some of the private railways like Keikyu and Meitetsu use 18m. I could run my Kato Keikyu Type 2100 Standard Set on R243 (Tomix) with no problems.  But the listing does not tell you that anywhere. You need prototype knowledge.

 

https://www.1999.co.jp/eng/10346807

Although the HobbySearch listing does not show the minimum turn radius. The instruction sheet does at R249. So C243 make normal sense.

 

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While prototype knowledge may help in the event an instruction sheet wasn't included. I would go to the instruction sheet first before second guessing.

 

Funly enough, PlazaJapan has actually listed the above quoted set with a minimum turn radius.

 

-----

 

Most prototype 18m 19m 20m etc etc from both Tomix or Kato will navigate R249 / C243. And be instructed as.

 

But when one buys a Tomix set and installs close couplers, you may need to up the minimum curve radi one.

 

I think from memory Tomix actually says something somewhere that some close couplers need C280 as a minimum. It may be freight sets, but not 100% sure.