Adapter pins

The Lionel 6-12746 seems to be an operating track for 027 that may do the trick.  Just noticed you mentioned this track in your post. I would probably shim it like you said.  In the past I have forced 031 pins into 027 track in a pinch.

Raising or shimming the height of the surrounding trackage and finding pins that will allow you to mate O-27 track to regular O are two related, but separate issues.

This thread should be helpful....

Correct adapter pins for joining Lionel O gauge track to Lionel O27. Gargraves 801 or 802? | O Gauge Railroading On Line Forum (ogaugerr.com)

Any tips on how to get these O gauge pins out of the operating track without doing to much damage? I've used a small screwdriver to widen the track under the pins  and then pulled with pliers but still meeting stiff resistance. I have the adaptor pins from Lionel to make the new connection,

The new track is crimped to hole the pins in, so sometimes you have to widen the bottom a little to pull them out.

I use a pair of diagonal pliers to grab the pin from the bottom and then leverage the pin out by moving the pliers to the underside of the track

Seems like a lot of work when just using an inexpensive 6019 track would work instead of the 5530.

@Bill Makel posted:

I use a pair of diagonal pliers to grab the pin from the bottom and then leverage the pin out by moving the pliers to the underside of the track

This is the way to do it Bill.

As to O to O27 conversion pins, I've ground down half of O gauge pins to O27 size to make them

@Lionelski posted:

As to O to O27 conversion pins, I've ground down half of O gauge pins to O27 size to make them

As long as you only grind the undersides of the pins, this works well. If you turn/grind down the entire circumference, it causes a huge transition bump.

@ADCX Rob posted:

As long as you only grind the undersides of the pins, this works well. If you turn/grind down the entire circumference, it causes a huge transition bump.

Here is a pic of the ones I made. As you can see it is not a huge difference between O and O27. They work great for me. I made and used them to convert the rails on my Bascule Bridge (O Gauge rails) to Warrenville's O27 height rails

The shiny ends are now O27.

@Lionelski posted:

Here is a pic of the ones I made...

Tapered might work OK. The 2948-10 pins from Lionel have a pronounced shoulder that causes a big bump.