In the other direction 1B01 is Fort William - Edinburgh, 1B16 is Aberdeen - Edinburgh and 1M16 is Inverness - Edinburgh where all three combine to run under 1M16 through to Euston
1C11 runs from Edinburgh to Carstairs where it joins 1M11 from Glasgow to run through to Euston as 1M11
all of which you can easily get by digging around on Real Time Trains ( or from the bit of paper on my desk
)
EDIT najaB beat me to my final flourish