Lenovo ThinkServer TS140 - Manual (Page 30)

Figure 7 “Drive bay locations” on page 18 shows the locations of the drive bays.
Figure 7. Drive bay locations
1 Primary optical drive bay (also can be used to install the fourth hard disk drive)
2 Secondary optical drive bay (also can be used to install a tertiary hard disk drive)
3 Secondary hard disk drive bay
4 Primary hard disk drive bay
18 ThinkServer TS140 User Guide