Query re Level Crossing Predictor Types

Can someone please explain the difference between  HXP and LXP level crossing predictors and also the difference between LXP type 3 and other LXP types.

What the reason would be for replacing HXP with LXP type predictors in association with upgrading infrastructure ? Also what reason for replacing existing warning bells at lx on Bairnsdale and Ararat  lines with  Cullen Hayes  type bells ?  ( an electric  warning bell is an electric  warning bell is it not ?)

LXP is a generic term used in the tender documentation "Level Crossing Predictor".  HXP (Harmon Crossing Processor) is the actual device supplied from one vendor, the other vendor supplies GCP (Grade Crossing Predictor).

In Victoria there are installed 3 different types of predictor:  HXP-1, HXP-3 and GCP3000.

The predictors being installed down towards Bairnsdale are Safetran GCP's.  The only reason one predictor is replaced with another one is usually when a HXP-1 is replaced by a HXP-3 for some reason, but IIRC this hasn't happned very much at all.

I'm not sure on why the WCH bells are being installed ilo existing bells, maybe there was a requirement to renew the existing bells?

On the subject of crossing bells on the Bairnsdale line. Only 2 days before the ones at Stratford were replaced, myself and one of the other local enthusiasts were standing at Hobson St commenting (to ourselves) that the striker on the old bell had just about worn its way through bell itself. It was ringing at the time as was the one at the Highway, even though no trains were anywhere near the town (but we're used to that here).

Interestingly enough, the signals were being repainted while this was happening. And only the day before this, we'd been thinking how much they could use a repaint. Coincidence?    Well, I guess it had been planned before we thought of it.

Anyway, I'm sure the bells had a few more years of life in them. I'll miss the lower pitched irregular ring of the Princes Hwy bell now.