Inverness - Aberdeen improvements

[adrock1976]

Having had a look at the Transport Scotland website, Phase I of the works Aberdeen - Dyce, and the reopenings of Kintore and Dalcross (under construction for the latter) have already been done. However, trying to find exactly what works Phase II is about is hard to find as I cannot find anything at all about it.

I am aware of the Scotrail/Transport Scotland aspirations of having Inverness - Aberdeen trains on a 60 minute frequency, with short Inverness - Elgin and Inverurie - Montrose also every 60 minutes each, so as to provide a 30 minute frequency.

Of course, the present infrastructure between Inverness - Inverurie would not be able to support a clockface 60 minute frequency, therefore (going by the Sectional Appendix: see pages 862-868) the only infrastructure interventions I can see is increasing the linespeed from a mix of 60-65 to a uniform 75mph between Inverurie and Elgin, and maybe some double track at the Inverness end. Would these be part of Phase II?

 

[Mcr Warrior]

Might one include the in-progress opening / re-opening of the station nearby to Inverness Airport (Dalcross?) as an upcoming improvement?

 

[hexagon789]

Having had a look at the Transport Scotland website, Phase I of the works Aberdeen - Dyce, and the reopenings of Kintore and Dalcross (under construction for the latter) have already been done. However, trying to find exactly what works Phase II is about is hard to find as I cannot find anything at all about it.

I am aware of the Scotrail/Transport Scotland aspirations of having Inverness - Aberdeen trains on a 60 minute frequency, with short Inverness - Elgin and Inverurie - Montrose also every 60 minutes each, so as to provide a 30 minute frequency.

Of course, the present infrastructure between Inverness - Inverurie would not be able to support a clockface 60 minute frequency, therefore (going by the Sectional Appendix: see pages 862-868) the only infrastructure interventions I can see is increasing the linespeed from a mix of 60-65 to a uniform 75mph between Inverurie and Elgin, and maybe some double track at the Inverness end. Would these be part of Phase II?

Phase 2 was to provide some double track between Nairn and Inverness giving more flexibility for an hourly service and to provide enough capacity to allow a half hourly Inverness to Elgin service to operate.

(As an aside - the double track, pre-1970s rationalisation, consisted of Aberdeen-Keith Jcn and Dalcross-Inverness. The remainder was always single track other than passing loops.)

 

[Wynd]

What are the odds of getting platform 8 & 9 in Aberdeen back in operation, with the respective North ticket office, and getting the Denburn and Hutcheon St tunnels back to double track?

Surely these would feature in Phase 2. Why no reinstate double track to Insch whilst we are at it.

 

[numtot12345]

My reckoning is the only way hutcheon st tunnel doubling would happen would be when they are electrifying up to Inverurie. Whether they actually double it is a different matter, as could just electrify the single track that is already there, however given the amount of work required just to do that is quite significant I believe. To me it would be completely shooting themselves in the foot if they didn't double it during electrification.

Doubling would certainly help any case for enabling capacity for services to Ellon and beyond too, as I believe the doubling here needs to happen to fit in anything more than an hourly service? Which is why the business case was so terrible when the last report on reopening line to Ellon was considered

 

[Wynd]

My reckoning is the only way hutcheon st tunnel doubling would happen would be when they are electrifying up to Inverurie. Whether they actually double it is a different matter, as could just electrify the single track that is already there, however given the amount of work required just to do that is quite significant I believe. To me it would be completely shooting themselves in the foot if they didn't double it during electrification.

Doubling would certainly help any case for enabling capacity for services to Ellon and beyond too, as I believe the doubling here needs to happen to fit in anything more than an hourly service? Which is why the business case was so terrible when the last report on reopening line to Ellon was considered

This is correct. Ellon had £50m of cost added to it because of the work required to fix the tunnels. This is what makes Peterhead a much stronger proposition with far more passengers and a realistic prospect of significant freight flows.

 

[Cheshire Scot]

Phase 2 was to provide some double track between Nairn and Inverness giving more flexibility for an hourly service and to provide enough capacity to allow a half hourly Inverness to Elgin service to operate.

Might a loop at Dalcross, and preferably a dynamic loop of a decent length be regarded as meeting this? Possibly allied to line speed improvements (see below).

Of course, the present infrastructure between Inverness - Inverurie would not be able to support a clockface 60 minute frequency, therefore (going by the Sectional Appendix: see pages 862-868) the only infrastructure interventions I can see is increasing the linespeed from a mix of 60-65 to a uniform 75mph between Inverurie and Elgin, and maybe some double track at the Inverness end. Would these be part of Phase II?

With the caveat I do not have an engineering background I would suggest there is potential to increase line speeds on much of the well aligned Elgin to Inverness section of the route to well beyond the present 75mph, also immediately to the east of Elgin. Further east whilst there is no doubt some scope to increase line speeds the route is quite curved in many places although to an extent making best use of the former double line formation on the single sections east of Keith to obtain an optimum alignment could help.

Mention of potential line speed increases usually brings comments about signal spacing but on a route that has predominantly traditional signalling systems with often many miles of plain line between signals this may only be a factor in terms of a potential need to relocate distant signals (or the TCB equivalent of a distant signal i.e. the signal(s) prior to the next stop signal), or reducing line speed to the current limit an appropriate distance before said signals e.g Elgin to Forres is around 12 miles so even leaving the distant signals in their current positions would offer around ten miles with potential for line speed increase subject to my next comments. A cautionary note would be there are a number of user worked level crossings on this section and indeed throughout the route and these (also 'conventional level crossings) would need to be assessed in terms of e.g. sighting times at higher speeds as well as for an increase in train service frequency. Bridges would also need to be assessed as there are a number of viaducts over rivers and lesser structures over both rivers and roads.

 

[hexagon789]

Might a loop at Dalcross, and preferably a dynamic loop of a decent length be regarded as meeting this? Possibly allied to line speed improvements (see below).

A dynamic loop is what I suspect was the intention, similar to the arrangement between Insch and Kennethmont but likely shorter.

With the caveat I do not have an engineering background I would suggest there is potential to increase line speeds on much of the well aligned Elgin to Inverness section of the route to well beyond the present 75mph, also immediately to the east of Elgin. Further east whilst there is no doubt some scope to increase line speeds the route is quite curved in many places although to an extent making best use of the former double line formation on the single sections east of Keith to obtain an optimum alignment could help.

Mention of potential line speed increases usually brings comments about signal spacing but on a route that has predominantly traditional signalling systems with often many miles of plain line between signals this may only be a factor in terms of a potential need to relocate distant signals (or the TCB equivalent of a distant signal i.e. the signal(s) prior to the next stop signal), or reducing line speed to the current limit an appropriate distance before said signals e.g Elgin to Forres is around 12 miles so even leaving the distant signals in their current positions would offer around ten miles with potential for line speed increase subject to my next comments. A cautionary note would be there are a number of user worked level crossings on this section and indeed throughout the route and these (also 'conventional level crossings) would need to be assessed in terms of e.g. sighting times at higher speeds as well as for an increase in train service frequency. Bridges would also need to be assessed as there are a number of viaducts over rivers and lesser structures over both rivers and roads.

There were already recent enough proposals to increase linespeeds to 90-100 on certain sections Elgin-Inverness.

Also, I have a document/file somewhere from ~1982 which discusses the potential for limited cost expenditures to improve journey times on Scottish internal routes. It outlines what speeds could be achieved without any significant signalling alterations (indeed preference for none). For Inverness-Aberdeen it states that certain sections could be upgraded to 90mph with minimal expenditure. As we know that still hasn't happened, but all the other proposals listed did happen between then and about 1985, so it wasn't pure fantasy.

 

[Cheshire Scot]

Is there not also an aspiration for a two hour end to end journey time - or have made that one up - a not unreasonable aspiration for a journey of 108 miles even with ten stops but certainly not achievable without some significant line speed improvements.

For example:
10 miles at 100 vice 75 = gain of 2 minutes
10 miles at 90 vice 75 = gain of 80 seconds which, depending on current section times might round to 1.5 minutes
10 miles at 75 vice 60 = gain of 2 minutes
Admittedly I have not taken account of the need to accelerate to and brake from these speeds, but decent uplifts in speeds do give decent time savings whereas a lesser gain in speed e.g. ten miles at 75 vice 70 only gives a gain of 40 seconds

 

[hexagon789]

Is there not also an aspiration for a two hour end to end journey time - or have made that one up - a not unreasonable aspiration for a journey of 108 miles even with ten stops but certainly not achievable without some significant line speed improvements.

For example:
10 miles at 100 vice 75 = gain of 2 minutes
10 miles at 90 vice 75 = gain of 80 seconds which, depending on current section times might round to 1.5 minutes
10 miles at 75 vice 60 = gain of 2 minutes
Admittedly I have not taken account of the need to accelerate to and brake from these speeds, but decent uplifts in speeds do give decent time savings whereas a lesser gain in speed e.g. ten miles at 75 vice 70 only gives a gain of 40 seconds

I think you are correct, ISTR aspirations for a 2-hour through timing as well.

As to the point of incremental increases reducing journey times - two historical examples both from May 1982:

HST differentials (often by only 5mph and by no more 15mph ie linespeed of 75 pushed to 90) introduced on Edinburgh-Aberdeen enabled a 16 min time saving for a 2hr 15min journey time with one 60 sec stop at Dundee.

Increasing linespeed between Perth & Dundee from 75 to 90 and reducing train timing weight by one 35 tonne coach to 245 tonnes (7 coaches) enabled an 8 min saving on Glasgow-Aberdeen journey times giving an even 2hr 45min timing.

Every little bit makes a difference.

 

[numtot12345]

Thinking longer term, the Decarb plan outlines alternative traction for this route. Would any of those potential solutions provide quicker acceleration than current HSTs, which would also help reduce JTs?

 

[hexagon789]

Thinking longer term, the Decarb plan outlines alternative traction for this route. Would any of those potential solutions provide quicker acceleration than current HSTs, which would also help reduce JTs?

The timetable is based on 156 performance - 75mph, I don't believe the sectional timings were adjusted when the 158s were cascaded, particularly as there was still a 156 job for about half a year and two on summer Sundays from memory (one went to Kyle).

The short HSTs could easily cut a few mins without any speed increases, if you then added in increases to say 90-100 you could save more, but pathing constraints with the single track sections may put pay to accelerating everything or everything equally, certainly that has happened previously when there have been speed improvements.

If you electrified that would have the HST acceleration potential plus a bit in terms of time savings without linespeed improvements, with linespeed improvements electrics have the potential to make better use of short upgraded speed sections. I believe for example a 385 can do 0-100 in about half the time the short HSTs can.

Presently as the plan is to run a mixed 158/170/HST timetable any improvements would need to be entirely speed related unless you deliberately risked timing the HST planned services a bit faster at the risk of late running if a DMU had to substitute.

 

[adrock1976]

Phase 2 was to provide some double track between Nairn and Inverness giving more flexibility for an hourly service and to provide enough capacity to allow a half hourly Inverness to Elgin service to operate.

(As an aside - the double track, pre-1970s rationalisation, consisted of Aberdeen-Keith Jcn and Dalcross-Inverness. The remainder was always single track other than passing loops.)

Many thanks.

I have had a go at designing a Taktplan and what I have come up with is illustrated below.

Keith​	​	​	​	1210​	​	​	​
Elgin arr​	​	​	​	1225​	​	​	​
Elgin dep​	​	1157​	​	1227​	​	​	​
Forres arr​	​	1208​	​	1238​	​	​	​
Forres dep​	​	1211​	​	1241​	​	​	​
Nairn arr​	​	1221​	​	1251​	​	​	​
Nairn dep​	​	1223​	​	1253​	​	​	​
Dalcross for Airport arr​	​	1233​	​	1303​	​	​	​
Dalcross for Airport dep​	​	1234​	​	1304​	​	​	​
Millburn Jct​	​	1240​	​	1310​	​	​	​
Inverness​	​	1242​	​	1312​	​	​	​
​	​	​	​	​	​	​	​
Inverness​	​	805​	​	​	​	​	835​
Millburn Jct​	​	807​	​	​	​	​	837​
Dalcross for Airport arr​	​	811​	​	​	​	​	841​
Dalcross for Airport dep​	​	812​	​	​	​	​	842​
Nairn arr​	​	822​	​	​	​	​	852​
Nairn dep​	​	825​	​	​	​	​	855​
Forres arr​	​	835​	​	​	​	​	905​
Forres dep​	​	839​	​	​	​	​	909​
Elgin arr​	​	850​	​	​	​	​	920​
Elgin dep​	​	​	​	​	​	​	925​
Keith​	​	​	​	​	​	​	940​

As you mentioned that there used to be double track Inverness - Dalcross, this could be easily reinstated.

The timings I have based on the existing section between Inverness and Elgin, with Elgin - Keith based on 75mph.

From both the Scotrail and RTT websites, I have noticed that Dalcross - Nairn, and Nairn - Forres has a run time of 10 minutes between each station/passing loop.

Also, the 1312 arrival at Inverness I have departing Aberdeen at 1112, meeting the aspirations of the 2 hour end to end journey time. However, some double track between Kennethmont and Huntly would be needed to be reinstated for a 60 minute frequency (based on increasing linespeed to 75mph Elgin - Inverurie), and having had a quick eyeball on Google Maps, this is a curvaceous section. I have the Keith - Aberdeen section in a separate document.

I do recall that it was either or both of @Bald Rick and @The Planner that had mentioned that increasing linespeed from 75 to 90mph results in the track having to have more frequent inspections, or something similar to that, which increases costs. Perhaps one or both could confirm?

 

[InOban]

I'm not in Inverness much now, but AIRC the tunnel which takes the line under the A9 is only designed for a single track. I think that the best you could get is a long loop from the A96 overbridge to the A9 tunnel.

 

[hexagon789]

As you mentioned that there used to be double track Inverness - Dalcross, this could be easily reinstated.

Assuming the formation still has the space, then presumably it could but is that a key upgrade necessary to deliver the aforementioned frequency and journey time improvements? I didn't think it was but perhaps I'm wrong.

Also, the 1312 arrival at Inverness I have departing Aberdeen at 1112, meeting the aspirations of the 2 hour end to end journey time. However, some double track between Kennethmont and Huntly would be needed to be reinstated for a 60 minute frequency (based on increasing linespeed to 75mph Elgin - Inverurie), and having had a quick eyeball on Google Maps, this is a curvaceous section. I have the Keith - Aberdeen section in a separate document.

The "takt" timetable you outline would be ideal for a more user friendly service, I would love if ScotRail could get the patterns tidied up again, they did manage it before but everything now is off by a few mins here and there hour to hour - very messy and unmemorable.

I would like to finally see the two-hour A2I timing achieved, it's been an aspiration for some time now but always seemingly put on the back burner in favour of other things.

 

[MadMac]

I'm not in Inverness much now, but AIRC the tunnel which takes the line under the A9 is only designed for a single track. I think that the best you could get is a long loop from the A96 overbridge to the A9 tunnel.

I walked through it some 35 years ago in the execution of my duties, and that was my recollection.

 

[Wynd]

2 hours end to end is the ambition.

Does anyone know what the ongoing work is around phase 2? Is there any?


Also, is there any publicly available software for making up timetables and timings that includes acceleration and deceleration?