Nowadays they still have to sign for the route but the knowledge is less detailed than the drivers and focusses on different things.
Speed limits and so on are less relevant (the highest speed you're going to encounter on a route is generally includes though.
You have to know the names of the running lines, controlling signal boxes and method of signalling, platform starting signals, all of the stations whether you stop or not and information about them (if they're manned, have step free access etc), electrification and which Electrical Control Operator is in control of it, axle counter areas, have a reasonable idea of where you are en route, junctions, passing loops, principle level crossings, tunnels, major structures like viaducts, anything specific to the route itself which may be required and a far greater depth of knowledge of the stations and train services themselves than the driver will have for customer service reasons, as well as in case of having to detrain there for example.
To be honest though once you've worked a route a while you'll know far more than the bare minimum - I certainly roughly know where most of the speed restrictions and signals are on my routes, as well as where I am, the things I'm less sure of are things like gradients that don't really affect me.
In addition the guard might be required to operate ground frames, train ready to start buttons at stations, some level crossings or undertake certain specific duties to a route (for example you have to report arrival and departure at Matlock to Network Rail by telephone).