I don’t know what type of grease rail greasers use, but I suspect it’s an adhesive type grease.
Point operating equipment uses a variety of lubricants depending on the equipment type. This includes petroleum based lithium grease, adhesive type grease, teflon based lubricants or PTFE grease.
Currently popular are Interflon Lube TF, Interflon Lube EP, Interflon grease MP1
Are the rats eating insulation on the railway?
I am surprised that railway signalling (and power) cables aren't damaged more often by rats. I know a lot of it stored in conduit, but that's hardly going to put off a determined vermin
Cable designed for installation outside is often designed to be rodent resistant - basically really tough outer layers that are specifically developed that their teeth won't be able to get a grip. Doesn't irradicate the problem but does massively increase the time taken to cause any real damage.
The sheath used for signalling cables, including 650V AC, 110V AC and 110V/120V DC signalling power cables is a tough rubber. The insulation is also rubber (PCP type). The telecommunications cables typically use polyethylene for the sheath. I’m not sure what the electrical distribution cables use.
Rats (and other rodents) don’t normally attack any of these cables. Whether lying on the ground, or in troughing. Except if they get to a constriction (for example where cables bend to exit the route or bend to turn via a T-piece junction). The do like using the cable routes / troughing as hiding places and as transit routes.
When they do attack cables, they don’t just gnaw the sheath and the insulation, but also cut through the copper cores. They are not so keen on metal (steel) armoured cable, but this is not used much these days.
Inside equipment location cases/cupboards/cubicles, mice are just as much a problem as rats. Again, most of the time they don’t touch the PVC or rubber cables and wires. Unless they get to a constriction. Or they are nesting inside an item of equipment, in which case where the nest is, they sometimes chew through both the insulation and the copper core.