You must have one of the last with the movable frog. The design got changed because the mechanism underneath the point is too easily jammed by a bit of dust or grit between the point and the baseboard leading to the frog directing the train a different way to the moving point blades. It never was a great mechanism design as the plastic pieces it is made from are not stiff enough to work reliably at the best of times.

Interesting discussion on this topic - several years ago I made the fatal mistake of placing ballast and dilute PVA adhesive too close to the movable frog mechanism. Out of frustration the useless 2275 went into in a drawer, and did not see the light of day until a couple of weeks ago. After several hours of study I decided that there could be nothing to loose by removing the immobile frog and replacing it with a similar sized and shaped item fashioned from a piece of old CD case plastic.
Bedded down with a spot of super glue and a couple of ‘check rails’ installed on opposite sides of the frog - the complete conversion turned out well and looks the part with some suitable Matt paint to blend it in.

If one of our members can instruct me on how to place a photo of the completed job - I would be grateful.