Why do services from Edinburgh and Glasgow to Inverness take so long?

[jagardner1984]

I don’t know the full weight / cost / speed, but given the linked discussion on HST replacement, I’m remembering my first journey on a 385 from GLQ, and obviously being familiar with what your brain thinks a journey should feel like (primarily on a 170 to that point) and feeling like the 385 shifting up that hill like the proverbial off a shovel !

It would seem electric / Bimode traction in the central belt would save minutes. Perhaps as HML full electrification seems a way off (ever) a similar principle of shortish stretches around key stations to allow faster acceleration might be more achievable ? Or in particularly hilly sections ?

The addition of longer or new passing loops in key locations to reduce pinch points or increase looping speeds.

Getting under 3 hours would be a good headline figure that would beat the road. And something psychological about a 6am train at either end that has you sat at your desk for 9.30 ….

Also surprised Loganair haven’t thrown in a journey or two …

 

[Bald Rick]

It’s pretty obvious why Loganair don’t run a service - the journey is too short, the airports are too far out of all three cities, the road journey is relatively good, and most importantly the number of people making the trip is way to small. In population and distance terms, it would be broadly equivalent of an air service from Liverpool to Boston in Lincs.

Reasonable to assume that electric trains (not necessarily electrification through out) and a clean path would see a sub three hour journey.

 

[hexagon789]

I don’t know the full weight / cost / speed, but given the linked discussion on HST replacement, I’m remembering my first journey on a 385 from GLQ, and obviously being familiar with what your brain thinks a journey should feel like (primarily on a 170 to that point) and feeling like the 385 shifting up that hill like the proverbial off a shovel !

The short HSTs aren't bad, but the 385s have to ease off quite quickly to avoid exceeding the 50 limit in the tunnel until it goes up to 60 about 2/3rds way up.

Logs and anecdotal information from drivers suggests a 170 will make about 40-45 by the top, a 158 35-40.

Of course it also helps that many platforms have a 25 limit out of them at Queen Street since the station rebuild, in the 170's heyday it was a blanket 15 until past the tunnel mouth crossover.

 

[snowball]

Perhaps as HML full electrification seems a way off (ever) a similar principle of shortish stretches around key stations to allow faster acceleration might be more achievable ? Or in particularly hilly sections ?

Full electrification of the HML, and of most of the Scottish network, by 2035 was still official Scotgov policy the last time anything was published, though inflation and other problems may have eaten into the timescale since then.

Partial electrification as a stepping stone seems a strong possibility. The location of any early electrified sections would be most influenced by possible locations of feeder stations, which on the last information we've seen would be at Faskally near Pitlochry and Avielochan near Carrbridge.

But even partial electrification of Perth-Inverness is a considerable way off. When the current round of electrifications is completed, the focus will almost certainly be on Dunblane to Aberdeen.

 

[takno]

Full electrification of the HML, and of most of the Scottish network, by 2035 was still official Scotgov policy the last time anything was published, though inflation and other problems may have eaten into the timescale since then.

Partial electrification as a stepping stone seems a strong possibility. The location of any early electrified sections would be most influenced by possible locations of feeder stations, which on the last information we've seen would be at Faskally near Pitlochry and Avielochan near Carrbridge.

But even partial electrification of Perth-Inverness is a considerable way off. When the current round of electrifications is completed, the focus will almost certainly be on Dunblane to Aberdeen.

Presumably it's not beyond the realms of possibility to use lower capacity connections in order to operate a single train in a short section, even if that train is accelerating uphill. The other possibility is to run an extension lead. I understand they'll soon have a spare one that's about the length of the line between Stalybridge and central Manchester.

 

[Railperf]

The network north of Edinburgh seperately needs modernisation and huge investment. There is still loads of semaphore signalling in use - and lots of low-speed track layouts at many stations that could do with simplifying and improving.
The highland main line has long stretches of single track. The last time I went to Inverness by rail, it was more convenient to go via Aberdeen. Plus it's easier to rent a car from Inverness airport than any downtown location - especially late in the day.

The main passing places are clearly Inverness to Culloden, Aviemore Station- which has modernised signalling and the dual track section between Dalwhinnie and Blair Atholl, Pitlochry station - which features an updated track layout and then the double track section between Stanley Junction and Perth.

Without further dualling, any speed improvements either side of each passing point need to be similar otherwise increased waiting times will become the norm with no improvement on the overall journey time. I.E you could theoretically speed up the Inverness to Aviemore time by a few minutes - but unless the train coming from Perth can be sped up between Blair Atholl and Aviemore, the southbound train has to wait its arrival to proceed south.

In reality if one of the trains is late then the passing manoeuvre ends up taking place at one of the lesser passing places - Tomatin, Moy, Schlod, Carrbridge, Kingussie, Dalwhinnie, Kincraig, and Dunkeld - which seem to have more restrictive signalling procedures which results in trains being brought to a halt before the loop and then -depending on priority each train is allowed to enter in turn and then depart. This adds huge amounts of time to any delay.
Quite a few trains are routed into the loops at Moy and Tomatin where they have to remain for quite considerable time to allow the train coming towards the loop a clear run through it. This adds unnecessary time to the journey

The dual track section between Blair Atholl and Dalwhinnie has a slower speed limit - 60mph uphill vs 80mph downhill - no doubt because the 158's 170's, IET and 2+9 HST's could never really achieve more than that. The 2+4 HST's are powerful enough to attain and reach higher -speeds, but the line speed profile does not appear to have been optimised for them. Therefore their better acceleration from station stops is cancelled out by 158's and 170's being allowed to run at higher speeds up and down hill, plus the units brakes are more responsive and can brake later/harder than the HST's too.

South of Perth, there used to me a shorter more direct route to Edinburgh via Kinross -which was ripped up. In previous years trains to Edinburgh have been routed along the single track route through Ladybank to join the slowish Dundee to Edinburgh route along the coast with its numerous low speed restrictions. Now it seems that trains take the slightly faster longer route via Stirling. In either case it is faster to drive from Edinburgh to Perth by road than either rail route. There are calls to rebuild a more direct route to Perth - but little likelihood of it happening. While the HML at present is only slighty slower than by car on a good day.

From a leisure travelling point of view the 2-3hr gaps on the highland main line are a disappointment. It can be just as quick to go via Aberdeen as there seems to be an hourly Edinburgh to Aberdeen service, and a quite regular service Aberdeen to Inverness.
An early morning Kings Cross to Inverness service would be a bonus.
Right now if i get the first Lumo service from Kings Cross to Edinburgh. The first direct service Edinburgh to Inverness would be almost a 3 hr wait and get me there at 1706. But the connection to Aberdeen and then Inverness is better, Getting me there by 1558.
Without investment - these rail lines - and destinations will not attract enough passengers!

 

[TT-ONR-NRN]

A 3h 40 - 4 hour long journey time is not competitive with flying*.

How many flights a day do you know of between Edinburgh/Glasgow and Inverness??

 

[route101]

Is Inverness -> Glasgow (or Edinburgh), direct, by air, even an option? Or vice-versa?

Not for some time. Last flight was a good few years ago from Edinburgh to Inverness. Flight went onto Kirkwall.

 

[BrianW]

What's the rush? What's key IMHO is to be able to get to where you want/ need to be at a decent time and return, leaving and arriving at an OK time.
And that's not only possible, but available now:

Inverness 05:36 - Glasgow QS 08:56 = 3h20
Glasgow QS 19:07 - Inverness 22:41 = 3h34

Glasgow QS 07:07 - Inverness 10:29 = 3h28
Inverness 18:53 - Glasgow QS 22:22 = 3h29
Inverness 20:23 - Glasgow QS 23:59 = 3h36

Edinburgh Wav 06:35 - Inverness 10:29 = 3h54
Inverness 18:53 - Edinburgh 22:26 = 3h33

Inverness 05:36 - Edinburgh 09:20 = 3h44
Edinburgh 19:39 - Inverness 23:17 = 3h30
+ 2 others e.w. - Edin arr 10:15 or 11:14; dep Edin 17:33 or 18:40

And all for a possible £24.10 return and relaxing looking out the window or working or chatting ...

What's so not ok about that? No worth £millions to save half an hour for no real benefit other than a headline and a photo-opp

By road: Glasgow 168.5 miles, 3h4; Edinburgh 156.5 miles, 3h5- according to AA. Without breaks, with or without refreshment; 25p/mile??

 

[JohnMcL7]

There's a lot of cherry picking going on there both for prices and times which don't match much of the reality speaking from experience of using said trains, the standard return price is £50 and I've found that's what I've had to pay to travel at times I'm needing, The service certainly does not offer the times I need to travel either as the last train leaves Edinburgh back to Inverness at just 19:38 so no chance of doing anything in the evening as I can in the car. Plus your timings don't include the ones that need to change at Perth which adds a whole chunk of time.

I wish what you were posting was the reality especially as I find the HSTs a much nicer ride than the constant intrusive engine noise of the 158s and the 170s but it's too much money given the tradeoffs especially the lack of a late train. I am realistic these days and realise there's never going to the usage to justify improving the HML and times but still frustrating.

 

[Railperf]

Todays 0644 Inverness to Edinburgh exemplifies the issues. Departs 12 min late from Inverness. Has an unscheduled stop at Slochd to accomodate a northbound train - losing another four minutes. Gets to Pitlochry 15 min late and then has to wait there for almost 13 min for the on-time northbound service. So leaves Pitlochry 28.min late. Makes up a couple of minutes to Perth ..but well out of path. The service is delayed further leaving Perth for an on-time Edinburgh stopping service to depart ahead if it. But from Perth southbound it makes up 10 minutes with a clear run to Haymarket in just over an hour to arrive around 15 min late. Had a similarly fast Azuma run Perth to Edinburgh during the strikes when very few scotrail services were running...giving LNER trains a clear run and much earlier arrival into Edinburgh.
So that indicates the Intercity times could be faster if there were fewer slower services on the network or infrastructure to allow faster trains to get past the slower ones.

 

[hexagon789]

What's the rush? What's key IMHO is to be able to get to where you want/ need to be at a decent time and return, leaving and arriving at an OK time.
And that's not only possible, but available now:

Inverness 05:36 - Glasgow QS 08:56 = 3h20
Glasgow QS 19:07 - Inverness 22:41 = 3h34

Glasgow QS 07:07 - Inverness 10:29 = 3h28
Inverness 18:53 - Glasgow QS 22:22 = 3h29
Inverness 20:23 - Glasgow QS 23:59 = 3h36

Edinburgh Wav 06:35 - Inverness 10:29 = 3h54
Inverness 18:53 - Edinburgh 22:26 = 3h33

Inverness 05:36 - Edinburgh 09:20 = 3h44
Edinburgh 19:39 - Inverness 23:17 = 3h30
+ 2 others e.w. - Edin arr 10:15 or 11:14; dep Edin 17:33 or 18:40

And all for a possible £24.10 return and relaxing looking out the window or working or chatting ...

What's so not ok about that? No worth £millions to save half an hour for no real benefit other than a headline and a photo-opp

By road: Glasgow 168.5 miles, 3h4; Edinburgh 156.5 miles, 3h5- according to AA. Without breaks, with or without refreshment; 25p/mile??

Todays 0644 Inverness to Edinburgh exemplifies the issues. Departs 12 min late from Inverness. Has an unscheduled stop at Slochd to accomodate a northbound train - losing another four minutes. Gets to Pitlochry 15 min late and then has to wait there for almost 13 min for the on-time northbound service. So leaves Pitlochry 28.min late. Makes up a couple of minutes to Perth ..but well out of path. The service is delayed further leaving Perth for an on-time Edinburgh stopping service to depart ahead if it. But from Perth southbound it makes up 10 minutes with a clear run to Haymarket in just over an hour to arrive around 15 min late. Had a similarly fast Azuma run Perth to Edinburgh during the strikes when very few scotrail services were running...giving LNER trains a clear run and much earlier arrival into Edinburgh.
So that indicates the Intercity times could be faster if there were fewer slower services on the network or infrastructure to allow faster trains to get past the slower ones.

The 0635 used to be the fastest Inverness to Edinburgh service. (Dep. Inverness 0648, arr. Edinburgh 0958.)

It was timetabled for 3h10, 20 years ago.

Faster is possible.

 

[3RDGEN]

From the latest FoFNL magazine, https://www.fofnl.org.uk/newsletters/23May/23may06.php.

As a tourist the journey times aren't an issue but the big gripe from local users is that a hourly service with significant journey time improvements was "promised" in 2008 and not much has changed. An hourly service may just be possible now but journey times would then worsen due to the pathing issues.

 

[Railperf]

There's a lot of cherry picking going on there both for prices and times which don't match much of the reality speaking from experience of using said trains, the standard return price is £50 and I've found that's what I've had to pay to travel at times I'm needing, The service certainly does not offer the times I need to travel either as the last train leaves Edinburgh back to Inverness at just 19:38 so no chance of doing anything in the evening as I can in the car. Plus your timings don't include the ones that need to change at Perth which adds a whole chunk of time.

I wish what you were posting was the reality especially as I find the HSTs a much nicer ride than the constant intrusive engine noise of the 158s and the 170s but it's too much money given the tradeoffs especially the lack of a late train. I am realistic these days and realise there's never going to the usage to justify improving the HML and times but still frustrating.

Seems to be £58.60 for a standard day return EDB to INV or save a tenner by split ticketing at Perth.

 

[BrianW]

There's a lot of cherry picking going on there both for prices and times which don't match much of the reality speaking from experience of using said trains, the standard return price is £50 and I've found that's what I've had to pay to travel at times I'm needing, The service certainly does not offer the times I need to travel either as the last train leaves Edinburgh back to Inverness at just 19:38 so no chance of doing anything in the evening as I can in the car. Plus your timings don't include the ones that need to change at Perth which adds a whole chunk of time.

I wish what you were posting was the reality especially as I find the HSTs a much nicer ride than the constant intrusive engine noise of the 158s and the 170s but it's too much money given the tradeoffs especially the lack of a late train. I am realistic these days and realise there's never going to the usage to justify improving the HML and times but still frustrating.

Thank you for responding. I live in Plymouth- a long way from your backyard and 237 miles from London, 4h13 via M4 and M5 (AA routeplanner).
Plymouth 05:55 - Paddington 9:01, 3h6; £160
Paddington 21:04 - Plymouth 00:4i, 3h37; £59
All times, tickets from Trainline currently.

My times and tickets Inverness- Edin/ Glasgow similarly from Trainline for next Tuesday- no cherrypicking! Sorry your trains are not more reliable. I had a trip to Wick and Thurso scuppered by a broken down freight train on single track section on an otherwise brilliant Spirit of Scotland ticket.

I can't think of anywhere that you could expect to see a show and get home same day on a 3-hour train journey- ready to be advised on that.

Bristol TM dep 21:45 arr Plymouth 23:43, 1h58? Choices to be weighed and made.

 

[takno]

I can't think of anywhere that you could expect to see a show and get home same day on a 3-hour train journey- ready to be advised on that.

Isn't the point rather that it shouldn't be a 3 hour train journey? I can't help but notice that London-Plymouth is a tiny bit further.

 

[A S Leib]

I can't think of anywhere that you could expect to see a show and get home same day on a 3-hour train journey- ready to be advised on that.

If you're starting in London there's a few places normally around two hours away with last departures after 23:00 (Derby at 23:05, Nottingham at 23:35, Wolverhampton at 23:30, Bristol at 23:32, Leeds at 23:33), which should be late enough to get from a play starting by 19:30 and lasting for two and a half or three hours. That is definitely the exception rather than the rule though.

 

[47271]

I use the HML a lot and timings north of Perth are pretty much unchanged since 2010.

The frustration I'm experiencing at the moment is the significant slackening of the timetable generally south of Perth since Edinburgh to Inverness trains started running via Stirling post Covid.

Take tonight's 1734 Edinburgh-Inverness. I wasn't on it but I can tell you that this service now leaves Edinburgh six minutes earlier than its pre Covid equivalent, the 1740 running via Kirkcaldy.

A combination of accumulated pathing allowances and lengthy timetabled dwells at Stirling and Perth meant that it arrived at Stirling eight minutes early at 1809 and left on time at 1823, a 14 minute wait. Its timetabled wait at Perth was 4 minutes, which it largely kept to. Is it really necessary for this train to take at least 18 minutes longer than it needs to before it enters the Highland Main Line?

It isn't just the Edinburgh services. Last night I was on the 1907 Glasgow-Inverness. There was no extended wait at Stirling, but at Perth we arrived 11 minutes early and were given a further ten minutes wait in the timetable, meaning at 21 minute dwell in one station alone.

None of this has anything to do with single line sections. It's difficult to come to any conclusion other than that the timetable has been padded?

 

[hexagon789]

I use the HML a lot and timings north of Perth are pretty much unchanged since 2010.

The frustration I'm experiencing at the moment is the significant slackening of the timetable generally south of Perth since Edinburgh to Inverness trains started running via Stirling post Covid.

Take tonight's 1734 Edinburgh-Inverness. I wasn't on it but I can tell you that this service now leaves Edinburgh six minutes earlier than its pre Covid equivalent, the 1740 running via Kirkcaldy.

A combination of accumulated pathing allowances and lengthy timetabled dwells at Stirling and Perth meant that it arrived at Stirling eight minutes early at 1809 and left on time at 1823, a 14 minute wait. Its timetabled wait at Perth was 4 minutes, which it largely kept to. Is it really necessary for this train to take at least 18 minutes longer than it needs to before it enters the Highland Main Line?

It isn't just the Edinburgh services. Last night I was on the 1907 Glasgow-Inverness. There was no extended wait at Stirling, but at Perth we arrived 11 minutes early and were given a further ten minutes wait in the timetable, meaning at 21 minute dwell in one station alone.

None of this has anything to do with single line sections. It's difficult to come to any conclusion other than that the timetable has been padded?

The Glasgow services have lost the three intermediate stops between Stirling and Perth, the departure times at Stirling and Perth stations are broadly unchanged - so you get chunks of pathing time between the two or an extended dwell at Perth or a mixture of both.

The Edinburgh services just suffer from sub-optimal poor paths along the E&G mostly.

 

[Clansman]

It’s pretty obvious why Loganair don’t run a service - the journey is too short, the airports are too far out of all three cities, the road journey is relatively good, and most importantly the number of people making the trip is way to small. In population and distance terms, it would be broadly equivalent of an air service from Liverpool to Boston in Lincs.

Reasonable to assume that electric trains (not necessarily electrification through out) and a clean path would see a sub three hour journey.

The only way you're getting an Inverness to Glasgow/Edinburgh flight is if the connection market is idenfitifed, in the same vein that Heathrow to Manchester/Newcastle predominantly exists for getting folk to Heathrow to connect on or from longer hauled flights, as opposed to London itself.

Even when thinking along those lines, I think Aberdeen would jump ahead of it too.

Interestingly KLM has this market monopolised for Inverness and Aberdeen with Amsterdam, which it can cross subsidise with its more profitable flights in the off-peak seasons - a luxury which Loganair doesn't have.

 

[47271]

The Glasgow services have lost the three intermediate stops between Stirling and Perth, the departure times at Stirling and Perth stations are broadly unchanged - so you get chunks of pathing time between the two or an extended dwell at Perth or a mixture of both.

The Edinburgh services just suffer from sub-optimal poor paths along the E&G mostly.

So would it not be better for the Glasgows to return to their old stopping pattern, the 1810ish ex Queen Street did Larbert-Stirling-Bridge of Allan-Dunblane-Gleneagles? Instead we have something that charges along and then waits for 20 mins, this has got to be the worst of all worlds. Long distance passengers are kept waiting and intermediate users get nothing.

Likewise the Edinburghs miss Grahamston, and then sit at Stirling for ages.

If it isn't timetable padding then it's lip service to the unrealised Inter7City ambition of fast services that only ever were supposed to call at Kirkcaldy or Stirling. Either way they're trying to kid us or they're kidding themselves.

 

[jagardner1984]

Also worth saying on the topic of that 1907 - it had dropped 4 minutes on route to Stirling and arrived on time, so there would have been added dwell there too.

Is there likely to be something in upsetting the Apple cart of HML timings that then knocks on to the broader Queen Street and Waverley timings ?

I note that the 385 Just before on the GLQ - EDB shuttle was over two minutes quicker by the time it passed Lenzie - so perhaps electrification to Perth or the much discussed BiModes for the I7C services might prompt a more widespread timetable recast ?

 

[Cheshire Scot]

Take tonight's 1734 Edinburgh-Inverness.

Interesting to note it was delayed at Dalwhinnie and was 8 late leaving Kingussie yet according to RTT contrived to arrive in Inverness 29 minutes early on amended public timings although actually on time on booked WTT timings having left the final stop at Aviemore 4 mins late. Has anyone any idea why the public timing was amended 'VVR' for today thus apparently missing the forward connections to Tain and Aberdeen (which in reality were made) whilst WTT times were unaltered - or is this a glitch on RTT?

 

[47271]

Also worth saying on the topic of that 1907 - it had dropped 4 minutes on route to Stirling and arrived on time, so there would have been added dwell there too.

Is there likely to be something in upsetting the Apple cart of HML timings that then knocks on to the broader Queen Street and Waverley timings ?

I note that the 385 Just before on the GLQ - EDB shuttle was over two minutes quicker by the time it passed Lenzie - so perhaps electrification to Perth or the much discussed BiModes for the I7C services might prompt a more widespread timetable recast ?

To be fair I didn't notice that when I was on it last night. The only reason it didn't have an extended dwell at Stirling because it left Queen Street late and passed Larbert four late. Then by the time it got to Auchterarder it was mysteriously four early.

No surprises that the 385 got to Lenzie 2 mins quicker, the Inverness was a 170 with very sedate progress uphill to Cowlairs.

I don't know the real causes, and how necessary they are, but Inverness services are definitely losing a lot of time south of, or at, Perth at the moment. Having all the extra power and acceleration available on HSTs, together with their fuel consumption, makes this all the more wasteful.

Interesting to note it was delayed at Dalwhinnie and was 8 late leaving Kingussie yet according to RTT contrived to arrive in Inverness 29 minutes early on amended public timings although actually on time on booked WTT timings having left the final stop at Aviemore 4 mins late. Has anyone any idea why the public timing was amended 'VVR' for today thus apparently missing the forward connections to Tain and Aberdeen (which in reality were made) whilst WTT times were unaltered - or is this a glitch on RTT?

Normal arrival time in Inverness is 2124, pretty much what it's always been, but I don't know what was going on tonight.

It's standard practice for the conductor to go through the train after leaving Perth to find out who needs the Tain and Aberdeen connections and to figure out what to do if they're going to be missed. That side of things is always handled extremely well.

 

[daodao]

South of Perth, there used to me a shorter more direct route to Edinburgh via Kinross -which was ripped up. In previous years trains to Edinburgh have been routed along the single track route through Ladybank to join the slowish Dundee to Edinburgh route along the coast with its numerous low speed restrictions. Now it seems that trains take the slightly faster longer route via Stirling.

The route from Edinburgh to Perth via Stirling is significantly longer than that via Ladybank. Pre-2020, trains could manage 75 minutes via Ladybank calling at limited stops. Scotrail have removed a significant number of trains from their timetables since Covid and increased the number of stops for some previous faster trains to compensate.

 

[47271]

I have few objections to the Stirling route for all Inverness services, it gives a lot more flexibility for changes if you're on an Edinburgh train and want to go to Glasgow, or vice versa. The only slight downside for me is that I've got no direct access to Edinburgh Gateway any more, but that doesn't do much other than make the place even more of an underused white elephant.

If they could just run to a decent schedule south of Perth then we'd all be a lot better off.

 

[computerSaysNo]

The route from Edinburgh to Perth via Stirling is significantly longer than that via Ladybank.

But it's also significantly faster; I believe it's all 80/90/100mph apart from the 40mph around Falkirk (and the 40mph at Stirling but you're stopping there anyway).
Whereas via Ladybank: you've got to accelerate to 80(?) past the Airport and then pretty quickly slow for the 50mph at the Bridge, 40/50mph to and through Inverkeithing, accelerate to 75mph through Dalgety Bay and Aberdour then down to 30mph through Burntisland, accelerate back up then brake again for the 40(?)mph at Kinghorn, back up then down for the stop at Kirkcaldy, then there's a 40 onto the single line at Ladybank, and then I think it's mostly 75mph after that. Remembering that acceleration isn't the 170s' strong point.

 

[MattRat]

Honestly sounds like the biggest problem is the lack of double track and old signalling. However, I image the costs for double tracking and modern signalling would be astronomical, so much so, it would cheaper to build a line that bypasses Aberdeen, and then use that new route to get to Inverness instead, as it would still be quicker than the current route.

 

[Grumpy]

The only way you're getting an Inverness to Glasgow/Edinburgh flight is if the connection market is idenfitifed, in the same vein that Heathrow to Manchester/Newcastle predominantly exists for getting folk to Heathrow to connect on or from longer hauled flights, as opposed to London itself.

Even when thinking along those lines, I think Aberdeen would jump ahead of it too.

Interestingly KLM has this market monopolised for Inverness and Aberdeen with Amsterdam, which it can cross subsidise with its more profitable flights in the off-peak seasons - a luxury which Loganair doesn't have.

Which is the right answer. In the late 1980’s BA and Loganair ran flights from the central belt to Inverness. I used them frequently and can recall a BA 748 setting off north from Glasgow approx0930 and returning approx 1700. Also a Loganair Twin Otter leaving Glasgow approx 1930. The best ever way to travel to Inverness was sitting on the front row of the Twin offer on a clear summer evening nothing behind the pilots and fabulous views through the front windows.
However the only direct flight to England was to Heathrow and these flights from Inverness gave connections at Glasgow to centres in the South. Since that time Inverness has gained direct flights to the likes of Amsterdam, Birmingham,Belfast, Manchester, Bristol, Luton and Gatwick. There‘s no significant connection market left.

 

[takno]

Honestly sounds like the biggest problem is the lack of double track and old signalling. However, I image the costs for double tracking and modern signalling would be astronomical, so much so, it would cheaper to build a line that bypasses Aberdeen, and then use that new route to get to Inverness instead, as it would still be quicker than the current route.

The line to Inverness doesn't go via Aberdeen