Gerry,
Whatever loco you have, I have two ways of putting on handrails. One way is to start at one end of the rails and insert each peg on the stancion one after another keeping the previously inserted stanchions installed. Usually my thumb has that job. The second way is to start in the middle and work your way out.
You can put quite a bit of pressure on the stanchions to ensure the peg is properly seated in the hole. This does not apply to the handrail that attaches to the bottom of the steps.
