Step 1: Understand the purpose of the drop warwick.
A drop warwick is specifically designed to engage the wheels of a runaway tub and arrest its motion in forward direction on inclines.
Step 2: Differentiate it from other safety devices.
(A) Monkey catch and (D) backstay are used in different safety contexts (often backward movement).
(C) Stop-blocks are physical barriers but are not the designated safety devices for automatic forward runaway prevention like drop warwick is.
| Feature in mine plan | Symbol | ||
| P | shaft | 1 | ![]() |
| Q | staple shaft | 2 | ![]() |
| R | Abandoned shaft | 3 | ![]() |
| S | Abandoned staple shaft | 4 | ![]() |

Pressure head characteristic of a mine fan and a mine characteristic curves are shown in the figure below:

Match the points with their corresponding nomenclatures