Im building my first O27 layout from my dad’s old post war set (Im 34), and was wondering if I should use insulated track to operate accessories such as the operating gateman and banjo signal, etc, or use the 153C contactor. Eventually, I would hope to have ballast and everything on the layout, so I wasn’t really sure how it would affect everything. FYI, I plan on running separate bus wires for the train, accessories, and switches/lighting (or accessories/lighting). Again, I’m new. Anyways, I love the hobby and was just looking for some advice. Soooooooooooooooooooooooooooo. O27 insulated or 153C contactor???
The contactor is only usable if they track is not fastened down and even then getting and keeping it adjusted can be difficult.
Many of the accessories will operate best from a section of insulated outside rail. Also its often better to power them not from the track power but another set of terminals on the transformer. A search of this site should turn up treads with the details of how to do this.
Scotie
Years of success with insulated track sections and accessories.
The main electrical difference between an insulated control rail and the 153C is that the 153C has a normally-closed contact. This is usually used with a signal (like the 153) to turn off one lamp while the normally-open contact turns on the other lamp. A typical workaround is to use the control rail to operate a relay and then to control the signal from the relay’s contacts. However, there is a simple trick that I have described here many times, for operating both signal lamps directly from the control rail. If you do have a signal to control, say so and I will be happy to find and post a description or a link.
If you hope to ballast the track, then the 153C contactor is out. It needs unfastened track that will move up and down slightly as the train runs over it. Also, the 153C can be a little touchy to adjust, especially if you have any light weight cars. I use insulated rails, they are more reliable than the contactors. If you get intermittent operation, then make sure that the wheels of your cars are clean and/or use 2 track sections in a row. You can also make your own track sections. 
I’ve used insulated tracks for those on/off accessories like crossing gates, gateman, etc. Never had a problem. I run conventional and have 12-14 volts for the loco and cars which is more than enough to trip the accessories and have them work well while the train is on the insulated track.
Can a copper strip laid on the track like those used on Marx accessories be used?
Thank you all for the advice. I appreciate it.
Yes to the copper strip (with insulation between it and the rail, of course). The downside is the bump, which you may find annoying.