Trouble with simulating an SCR
Below the trigger current, the SCR will act a bit like a transistor, so the gate current will be reflected in the anode current. 

When the trigger current is reached, 200uA minimum in this case, the positive feedback takes over (given a sufficiently low load resistance) and the SCR latches on until the current drops below the holding current (stated as 5mA maximum for this part, but typically closer to the trigger current). 

Edit: I don't have a working 2N5060 model,and I'm not going to import one, but here is the behavior with a 2N6564 which is similar. I've reduced the gate resistor and the load resistor. You can see the jaggies in the anode current near the zero crossings due to not reaching (or maintaining, on the falling edge) the minimum holding current. 



The lack of triggering at low current may be a timing thing- the 200uA is okay for DC but not for 50usec pulses, or it could be a problem with the model, you can poke it and find that out.