pennylane2

I currently work full-time (3/12's) nightshift in ICU. Our current inpatient dialysis dept is staffed with one main dialysis nurse and a couple of others who work on call on weekends to give the main nurse a break (so she's not on 24/7). The opportunity arose to train into dialysis as another part-time nurse. After accepting, I found out that one part-time nurse gave notice and another is retiring next summer. The main nurse is planning on retiring in approx 5 yrs and is hoping I would train and move into her spot permanently and at that time I would be it! At first I had no problem with this, but now I am finding that they have no guaranteed plan for training me. I still work my 3 night shifts, and they call me on my off days to come in when there is a new inpatient that need treatment. I have seen and helped only a handful of times since April because of the lack of opportunities when I'm off work. The only guaranteed training is to send me out of town for a couple of weeks to another facility to have a solid 2 weeks of 9-5 shifts, but even that is not necessarily the exact training I would need to do this job safely. I have asked for guaranteed hours to come in, but have been told the budget doesn't allow for it, since there could be times there are no patients. I have felt guilty when I have to work and they call to tell me there is a pt, but I can't come in to train. I feel like this is becoming a waste of time for all parties. I also don't like saving my days to be on call "in case" a pt comes in, and can't plan anything in depth at home. I think I want to just tell them this isn't working out, but I'm not sure how to tell them. I don't want there to be hard feelings, but I also feel like it's on them for not having a specific plan in place for training. Can someone tell me what their experiences have been to become trained in this area? And does anyone know how I can politely get out of this situation?