For the most part they will, however there are exceptions. You will have to compare the various manufactures and see if their products are the scale [size] you want and if you must make any conversions to allow it to run with your other equipment. The biggest challenge is the variety of couplers offered. To overcome this issue you simply select the coupler that works best for you and convert your equipment to the same coupler.
There is a size issue here with some however. You’ll find that the European prototype Marklin Trains, being a smaller scale, will not match up with most other large scale.