layout size.

[19frogger69]

I want to put a train up for Christmas. Since room will be an issue; What is the  smallest diameter curve that can be used ?

[Jerrys HO]

Hey Froggy,

Depends on the loco and rolling stock. What scale are you inquiring about? How much room is available?

Jerry

[Jerrys HO]

To give you an idea this pic is from one of our members and is in HO scale.

http://i792.photobucket.com/albums/yy202/NarrowmindedRR/minilayoutbridge001.jpg

Jerry

[jbrock27]

I believe it is usually a 15 degree arc and can be found made by various manufacturers and gauges.  This is for a piece of sectional track.  As Jerry touched on, this impacts the size (length) of the loco and rolling stock (cars) you can run on that small an arc.  They will have to be the smaller variety to stay on the rails.
To Jerry's question, what scale are you inquiring about?

[Doneldon]

froggy-

I hope you are considering doing this with either O-gauge or large scale trains. HO is a little delicate to be on the floor under a tree. I have a large scale twice around (easy to do with a crossing) which is roughly 42" across. That's a good size because tighter curves would pull the trains so far under the tree that it would be extremely difficult to see them.
                                                                                                                                                                                  -- D

[Loco Bill Canelos]

I strongly recommend a nice G Scale set from Bachmann.  There are two great sets, one is a passenger set 90076 Called the White Christmas Express which has the loco two passenger cars the track and power supply all included. It has 20 pieces of track and is about 4 feet by 8 feet. The other is a freight set 90037 Night before Christmas with the loco and a gondola and caboose. it has 14 pieces of track and cover a 5&1/2 by 40 foot space.  If you prefer a non christmas theme set there are many of them as well.  to see pics load this and go to page 168.
http://www.bachmanntrains.net/Catalogs/2013/2013_Bachmann.pdf  don't be put off by the MSRP prices, the swets are sold at great discount prices.

RLD hobbies has great prices on sets, and ships fast.  http://rldhobbies.com/startersets.aspx   

Call to see if he has the christmas themed sets, he definitely has several nice sets.  Robbie the owner answers the phone personally and will help you after the sale if necessary.

TrainWorld also has great prices and ships fast.  There are others as well but I mention these two because they have given me great service and lowprices in the past.

Have fun and have a great Christmas!!

Loco Bill

[GG1onFordsDTandI]

froggy-
I hope you are considering doing this with either O-gauge or large scale trains. HO is a little delicate to be on the floor under a tree. I have a large scale twice around (easy to do with a crossing) which is roughly 42" across. That's a good size because tighter curves would pull the trains so far under the tree that it would be extremely difficult to see them.
  -- D

I strongly recommend a nice G Scale set from Bachmann.  There are two great sets, one is a passenger set 90076 Called the White Christmas Express which has the loco two passenger cars the track and power supply all included. It has 20 pieces of track and is about 4 feet by 8 feet. The other is a freight set 90037 Night before Christmas with the loco and a gondola and caboose. it has 14 pieces of track and cover a 5&1/2 by 40 foot space.  If you prefer a non christmas theme set there are many of them as well.  to see pics load this and go to page 168.
http://www.bachmanntrains.net/Catalogs/2013/2013_Bachmann.pdf  don't be put off by the MSRP prices, the swets are sold at great discount prices.
RLD hobbies has great prices on sets, and ships fast.  http://rldhobbies.com/startersets.aspx   
Call to see if he has the christmas themed sets, he definitely has several nice sets.  Robbie the owner answers the phone personally and will help you after the sale if necessary.
TrainWorld also has great prices and ships fast.  There are others as well but I mention these two because they have given me great service and lowprices in the past.
Have fun and have a great Christmas!!
Loco Bill

The Christmas train is a great tradition. Many of my family set one up, mostly O.
Both these guys have great suggestions.
HO- less $, more detail, fragile but quiet. Depends on the household.
I give O-27 the edge for small size dia. track. Full O tubular on durability(normally heavier metal than 0-27). Plastic roadbed track for a "perpetually new & clean" look. Engine durability overall, esp. if it is cast. And often overall best for reparability, and parts I think.
G is the winner for quiet operation -vs- being seen, and ability to load larger toys for hauling. Brass track, if not stored well, will require attention every year.
Though 0-27 is the smallest curves, a 36" or larger circle/oval seems easier to "work" around, and I find it more visually pleasing if the train runs around gifts, rather than gifts forming a wall around the train. Also attaching a tree stand to a track sized piece of heavy plywood(covered with a fireproofed fleece) will keep your tree standing despite the best efforts of others, its also smart for deep shag carpets. The hardwood floor should be protected too, even the plastic stuff can scuff eventually with enough "laps". 

[phillyreading]

Depends on what space you have to set up in.
H.O. takes about 3 feet for their smallest curve size, unless you buy flex track.
027 track(similar in size to O gauge) uses less then 30 inches for it's smallest curve.
O gauge, 031,  takes about 32 inches for a circle.

Not sure in other gauge or sizes.

Lee F.

[hhartman]

I have a large scale twice around (easy to do with a crossing) which is roughly 42" across.

Don,

Any chance of posting that track plan?  I have a Lehman Christmas train that I put under our tree every year and the plain oval has become plain boring!

Harvey

[Doneldon]

Harvey-

I'll get to it this weekend. I must bring the train up because we put our tree up today.

                                                                                                                      -- D

[hhartman]

Thanks.  I'll look forward to it.

Harvey