I have seen two variations of instructions 7860:
1) For the second release 1982-87, the code of instruction is 113483 ©1981. In the instructions, we can see this variation of "Straight Conducting Rail with Rail Interruption" 3242apb01:
https://www.bricklink.com/v2/catalog/catalogitem.page?P=3242apb01&idColor=9#T=S&C=9&O={"color":9,"iconly":0}
2) For the third release 1988-94, it is 120622 ©1981 in which we can see this variation of "Straight Conducting Rail with Rail Interruption" 3242bpb01:
https://www.bricklink.com/v2/catalog/catalogitem.page?P=3242bpb01#T=S&C=9&O={"color":9,"iconly":0}
3) What about the first release 1980-81? Is there any instructions for it (do you have it?) in which we can see "Straight Conducting Rail with Rail Interruption" 3242a:
https://www.bricklink.com/v2/catalog/catalogitem.page?P=3242a&idColor=9