What is a saw-by?

It's where the trains are too long for the loop.

Some variant of......

A--------B-----------C----------X--------\ \ \ \--------Y----------D-----------E---------F

Eastbound train1 stops at A.

Westbound train2 stops at F.

Train1 (at A) is split in the middle. Train1's front half stops at X, leaving the rear half still at A.

Train2 goes completely through the loop to B.

Train1's front half moves forward to F clearing the loop.

Train2 couples up to the rear half of the train1 at A.

Train2 backs up into the loop, pulling train1's rear half which it drops off at X.

Train2 continues backing up to stop at E.

Train2 drives forward via Y, passing train1's cars it left at X, without stopping and continues its journey.

Train1 at F backs up to couple onto its rear cars at X.

Train1 then drives forward to continue its journey.

Phew.

When two trains that are each longer than a passing siding meet, some shuffling is required. As an example, imagine a single ended siding half the length of the train. One train cuts it's rear half and leaves it on the main line beyond the turnout. The loco half then runs past the turnout and backs in, thereby clearing the main line. Train two passes and pushes the other half further away until train two is clear of train one. Train one returns to the main line and moves one and a half plus train lengths away. Train two backs up, hauling train one's rear half which it then propels into the siding. Train two then bcks from the siding, leaving the rear half of train one clear on the siding. Train two departs. Train one backs onto the half in the siding, couples on and resumes it's journey.

With the two good descriptions (at the time of my reading the NG), imagine the fun if the two trains both were more than twice the length of the siding!

-- Why isn't there an Ozone Hole at the NORTH Pole?

You can also do a saw-by if only one train is longer than the siding.

Your 'fun' sounds very > With the two good descriptions (at the time of my reading the NG),

Then you need to saw-by three or more times - don't give up, the rest of us will just go and have a beer until you've cleared the main line! ;^)

Regards, Greg.P.

You can but why would you? Keith Make friends in the hobby. Visit Garratt photos for the big steam lovers.

Phew.

Because, as far as I know the other version is a double saw-by.

Thanks gents. From how my FIL was trying to explain it, I never understood that one of the trains was uncoupled in the middle somewhere so I could not figure out how it could be physically possible (which of course it couldn't be). Is this a common maneuver these in modern railroading?

When you consider that splicing helpers into the middle of a train out on the mainline is rather rare in model railroading, doing sawbys where the uncoupling is even more random is going to be even more rare. I've done it a few times with some big trains on large layouts but there tends to be a lot of grumbling when such things happen as the process takes a while.

-- Why isn't there an Ozone Hole at the NORTH Pole?