Table:
0
A
B
C
D
E
1
County
Tunnel
Type
Length (Imperial)
Date of opening
2
Londonderry
Castlerock
Rail
668 yd
1845 - 1853
3
Londonderry
Downhill
Rail
307 yd
1845 - 1846
4
Armagh
Lissummon
Rail
1759 yd
early 1860s
5
Down
Binnian Tunnel
Aqueduct
2.5 miles
1948 - 1952
6
Antrim
Whitehead
Rail
145 yd
1862 - 1994
7
Tyrone
Dungannon
Rail
800 yd
1862

Questions and formulas:
Question: What Tunnel has an Imperial Length of 307 yd?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:E1,D1="307 yd"),2))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:E7,D2:D7="307 yd"),2))
Level: medium
Question: What Type of Tunnel is the Downhill Tunnel?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:E1,B1="downhill"),3))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:E7,B2:B7="downhill"),3))
Level: medium