Question : Problem: What is the correct rack rail kit for Compaq R3000h (3U) UPS part 242705-002

I have two Compaq R3000h UPS devices acquired 2nd hand but have no rails for rack-mounting. New, they came with fixed adjustable rail kits but have obviously been discarded sometime. None of the documentation I have found gives me the part number for the rails and Google comes up with about 4 different parts.

Can anyone tell me the correct part for these 3U UPS devices? I mention they are 3U because I already have, in a different location, a 2U R3000XR and the rails for this have a full length support underneath, but a short top support to hold the UPS. Obviously, in this case, the height of the UPS is important.

Now, if anyone in the UK has a set going spare, that's even better - more than just points going!

Answer : Problem: What is the correct rack rail kit for Compaq R3000h (3U) UPS part 242705-002

If you look in the actual -service- manual for a R3000h there will be a part number for the screws to hold those rails on too.
They will be the same screws used in 100's of other Compaq devices and each of those devices will have a different part number for the screws.

That's how Compaq did part numbers and the part you are looking for was not offered separate from the unit.
There was no 'advertised' part number for it because it wasn't sold on the open market, only as a replacement part that you had to order direct from Compaq.
If you want that EXACT PN then you will have to order direct from HP and hope they care enough about your business to look that far back in Compaq's catalogs to find it. Given it's age, I'm quite sure you will be sent an alternate PN anyway. Probably one of the ones on the list you've been making.