RE: Small Favor to ask of Lionel Visionline/JLC Bigboy Owners

Well, I don't have a picture, but I can tell you that the overhand is just a touch over 3" from the center rail on an O72 curve using Atlas track.

My outside 072 is 3 5/8" from back wall, (measured from center rail) and my Vision BB makes it.  I just measured distance, sorry my BB isn't on track right now, rather in my office so couldn't take a photo.

Just to be safe, on O72 Fastrack, I leave at least 2 inches between the edge of the ballast and my living room furniture and since my track is on carpet, I check for movement of it before I go cruising the Big Boy.

gunrunnerjohn posted:

Well, I don't have a picture, but I can tell you that the overhand is just a touch over 3" from the center rail on an O72 curve using Atlas track.

Just happened to be putting in dwarf signals yesterday.  Moved them outward 2 times.  Bigboy has the longest snout I've run across.  If Bigboy fits, anything else will.  Sorry I did not measure.

When I took my VL-BB to the club, we found out that three tunnel portals were too narrow, and a number of landscape items were too close to the tracks.   There is also a "Big Boy Notch" in one track-side building to let the locomotive walkway clear, I have to slow way down there to just ease on by.

If you have other big locomotives like the DD40, make sure you get the inside overhang meaurments. If the dd40 is on the outside curve , and the bigboy is in the inside curve that could get ugly if they meet at the wrong time.

With 5.5" spacing on O99 curves, I was able to knock some 21" passenger cars off the track with the VL-BB, however the brute just kept on chugging around while they picked up the pieces.   My new layout is going to sport 6" between tracks for that reason.

Gentlemen, 

I appreciate the feedback and interest in my post. I'm having a bit of chuckle at the comments and the feedback. Please forgive me, for I know how tone sometimes can and will be lost in emails, but I run nuclear submarines for a living which has plagued me with a proclivity for precision. I've seen this thread before with pictures of Big-Boys top down and on various curves, but all of them were lacking a "prime standard" or a measurement. Lionel can do the community a service if it presented the limiting overhang values for prevention of mutual interference (i.e. not to hit stuff) in the manuals for the popular iteration of curves (O-72, O-80/81/82/90 etc...), but they haven't. Here's what we know and what we need to know to take the mystery of all of this out of the equation. 

• Lionel "Scale" Big Boys minimum curve operation, unaltered from the factory and with tender is O-72.  (I think the community agrees on the tender as the actual limiting component) 
• The maximum limiting overhangs are as follows:
  • Boiler Overhang = "X" inches from the center rail (I think center rail seems to be a good reference point and different manufacturers align here)
  • Cab or Tail end = " "
  • And if you want to get even more specific due to ground items like signal lights a vertical clearance. 

If we are armed with this information we can account for everything as we build, modify, and carry out dual track operations. 

If anyone has a picture with a measuring tape I'll send you a fruit basket. I know, I'm actually asking you to play with your BigBoy, which sounds funny. 

Cheers 

VR

Chris

I used to design flight critical avionics  for a living, and I was way more precise when I was designing that stuff.  However, this stuff is model trains, and people don't die if I get a track clearance wrong.

Here you go. VL Big Boy on Lionel O-72 Fastrack.

If you draw a straight line down from the corner of the walkway, it would be right at the 1.5” line.

One thing worth remembering...there is a fair amount of play at the front of the boiler. It’s capable of moving over/under that 1.5” line. Best to leave plenty of extra room!

Hope this helps.

Thanks, Ron, super helpful! 

yankspride4 posted:

Here you go. VL Big Boy on Lionel O-72 Fastrack.

If you draw a straight line down from the corner of the walkway, it would be right at the 1.5” line.

One thing worth remembering...there is a fair amount of play at the front of the boiler. It’s capable of moving over/under that 1.5” line. Best to leave plenty of extra room!

Hope this helps.

For safety you'd need to leave 3-1/2" to 4" off the O72 track centerline? We're posting the No BigBoy sign! Does the UP Challenger overhang the same amount?