Grantham South Junction line speed for diverging route should be increased

[Railperf]

Moderator note: Split from

Overspeeding incidents at Grantham South Junction - 25/2/25 & 26/9/25

Mod Note: This thread initially concerned only an incident on 25 February 2025 but another incident occurred in September 2025 at the same place. Discussion of this later incident starts here. BBC report Staff onboard a train were left hurt after it travelled through a junction near a market...

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Why do we have such a ridiculously low speed turnout in this location? Surely it should be replaced with one capable of handling trains at 50 to 60mph so that trains diverging onto it can clear the main line quicker?

 

[zwk500]

Why do we have such a ridiculously low speed turnout in this location? Surely it should be replaced with one capable of handling trains at 50 to 60mph so that trains diverging onto it can clear the main line quicker?

When the layout was designed, how much money was available and how often was the Down Slow used to regulate fast passenger trains?

 

[TreacleMiller]

Why do we have such a ridiculously low speed turnout in this location? Surely it should be replaced with one capable of handling trains at 50 to 60mph so that trains diverging onto it can clear the main line quicker?

Track layout and location of the next road Bridge, signalling and the height change at this location between the slow and fast line (there is one, not much but it's there at that point) does not help.

40mph up the slow too so any faster points would be useless.

It's an easy done thing at his location, especially when stopping, with extra care needed.

I simply don't take full power leaving Grantham going south in an 80X. Isn't as much of an issue in a MK4 provided youre visually checking the points to double check you haven't somehow missed the junction indicator.

 

[najaB]

Track layout and location of the next road Bridge, signalling and the height change at this location between the slow and fast line (there is one, not much but it's there at that point) does not help.

40mph up the slow too so any faster points would be useless.

In that case, it seems that replacing the 25mph crossover with one rated at 40mph wouldn't be a bad idea. If only so that trains wouldn't have to slow down to speed up. And one would assume that in the event of another incident the result of a 50mph overspeed across 40mph rated pointwork would be less severe than over 25mph pointwork.

 

[ChilliSauce]

In that case, it seems that replacing the 25mph crossover with one rated at 40mph wouldn't be a bad idea. If only so that trains wouldn't have to slow down to speed up. And one would assume that in the event of another incident the result of a 50mph overspeed across 40mph rated pointwork would be less severe than over 25mph pointwork.

As this turn out is after a set of trailing crossovers then it might not be that simple as the switches would have to be longer to accommodate the higher speed making the loop shorter.

Just modification to the interlocking to place the "Read through" signal at Red when the turnout is reverse should be much simpler and thus very much cheaper ... Remember if the turnout is replaced with 1 of a longer switch length then the OLE would also need a "Tweek"

 

[Annetts key]

I suspect replacing the crossover with a higher speed one would require a complete relaying of the whole junction.

That's unlikely to happen anytime soon, certainly very unlikely until there is another reason for relaying.

 

[najaB]

Just modification to the interlocking to place the "Read through" signal at Red when the turnout is reverse should be much simpler and thus very much cheaper ... Remember if the turnout is replaced with 1 of a longer switch length then the OLE would also need a "Tweek"

If the only goal was to reduce the risk of a repeat read through and overspeed, yes. But eliminating the 25mph speed restriction would have benefits every time the crossover was used (I've no idea how often that is).

I suspect replacing the crossover with a higher speed one would require a complete relaying of the whole junction.

Most likely, yes.

 

[edwin_m]

I would have thought it was quite unusual to put an 80x onto the slow line here, as it's the fastest train on the route so would keep ahead of any following train. The only reason I can think of is regulation being needed, which for some reason can't be done further south.

Freight and the EMR service are less at risk of this particular overspeed situation, freight because it has much less acceleration. EMR also has less acceleration, plus it will already have used 25mph turnouts from platform 4 before reaching this one.

 

[zwk500]

But eliminating the 25mph speed restriction would have benefits every time the crossover was used (I've no idea how often that is).

From looking at publicly available berth data, very rarely.

I counted 1 time in the last 6 weeks when an ordinary LNER train was routed onto the Up Slow. Its more common for the EMRs to use it but as mentioned they're coming from P4 which has a 25mph turnout anyway.

 

[najaB]

From looking at publicly available berth data, very rarely.

I counted 1 time in the last 6 weeks when an ordinary LNER train was routed onto the Up Slow. Its more common for the EMRs to use it but as mentioned they're coming from P4 which has a 25mph turnout anyway.

That changes the cost/benefit ratio significantly, almost certainly not worth it then.

 

[sharpener]

I simply don't take full power leaving Grantham going south in an 80X. Isn't as much of an issue in a MK4 provided youre visually checking the points to double check you haven't somehow missed the junction indicator.

Sounds good practice. How fast can you be going and still read the lie of the points and brake to 25 mph though? It does mean if not taking the turnout you don't take advantage of the full performance until after that point.

What do you think of the idea in the other thread of holding the next (fast line) signal at a restrictive aspect if you are going to be diverted?

 

[Twingo37175]

From looking at publicly available berth data, very rarely.

I counted 1 time in the last 6 weeks when an ordinary LNER train was routed onto the Up Slow. Its more common for the EMRs to use it but as mentioned they're coming from P4 which has a 25mph turnout anyway.

As far as I am aware (and commented on the other thread) it was previously used each day to get the 07.00 Hull to London (LNER) out the way of the 5.40 Edinburgh to London, which was also one of the previous overspeed incidents. With the new timetable, that now occurs at Peterborough as the Edinburgh service runs a few minutes later.

 

[dk1]

Hasn’t it all been recently renewed? From what I can see everything was just like for like. It’s done very differently in Scotland to England it seems where junction/loops are often improved.

 

[Annetts key]

Hasn’t it all been recently renewed? From what I can see everything was just like for like. It’s done very differently in Scotland to England it seems where junction/loops are often improved.

The general principle for Network Rail in England (I can't speak about elsewhere) is that unless there is money in the improvement budget (which is not very big) or there is funding from elsewhere, all renewals are like-ish for like-ish. As in unless improvements can be made at no extra cost, there won't be any improvements other than restoring the infrastructure back to the previous design specification (i.e. removing temporary speed restrictions or similar).

That's why I thought that in the past it was misleading when they made claims that lines being closed for normal heavy maintenance or like for like renewals was "improving the railway".

 

[najaB]

That's why I thought that in the past it was misleading when they made claims that lines being closed for normal heavy maintenance or like for like renewals was "improving the railway".

Well, technically they are improving it from how it is, though only back to how it should have been in the first place.