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West Hampstead

Panel 3

Ground Frames

This panel features a number of ground frames. Generic operation of these are explained in the section on Lever Frames with specific detail below.

Cricklewood Maintenance Ground Frame

This rarely-used connection allows access to the far west/north end of the Cricklewood Depot complex. It is not possible to access the depot from the Up Slow directly as there is no suitable signal to do so. However, Down trains can approach signal WH241 and reverse into the depot from there.

As the name suggests, access is controlled via a ground frame . The signaller releases the frame by left-clicking on the F circle for ground frame 969. After a timeout has expired, the frame operator can reverse the Release lever. Each point end is controlled separately, with the facing Up Slow point end locked by the Facing Point Lock which must be reversed in order to reverse that point. Once the points are in the correct positions, the ground frame operator may give virtual hand signals to the trains using the switches provided to authorise a train to move.

Once the manoeuvre is completed, the frame may be restored to its normal position and the signaller can take the release back.

Hendon Lines

Map

These unelectrified lines allow freight trains to escape the main lines onto their own dedicated lines. However, the line speed is low - only 10mph over the Silkstream flyover and up to 30mph elsewhere.

Along much of their lengths, the lines allow permissive working for freight trains. This means that a second train can be signalled into the same section as a preceding one. In fact, a third or more could be, space permitting, but the TD will only remember up to two trains at a time per signal section.

Note that there is, in general, no TD stepping from the shunt signals along this section.

Mill Hill Broadway

Map

Though shunt signal WH588 appears to be close to Mill Hill Broadway station, it is in fact over 800m away. The signal is provided for emergency use and scheduled passenger workings are not permitted. As there is no signal for moves from the Up Slow to the Down Slow, movements can only take place from the Down Slow to the Up Slow.

A ground frame is provided for the Fast lines. This is for emergency use and is rarely used. The ground frame has three levers and two virtual signals. The signaller gives the release in the normal way by left-clicking on the F circle. Once a timeout has expired, the ground frame operator can take the release by reversing the Release lever. Each end of the points needs to be operated separately, after which one of the virtual signals can be used to authorise a train to move over the ground frame. The signals, points, and then Release lever need to be normalised, after which the signaller can take back the release by right-clicking on the F roundel.

Radlett Junction

The route from the Up Slow to the Up Fast is signalled for a flashing yellow approach. The linespeed over the diverging route is the same as for the other diverging routes over the junction though!

Radlett Redland Road Stone Siding

Map

Access is only available in the Up direction. A telephone call must be made to the siding before sending a train in, to ensure that the locked gate is open. Trains from the St. Albans direction can head straight in from signal WH258. Trains outbound towards St. Albans can also head out via signals WH479 and WH267.

Trains from the south need to reverse at signal WH592. There will be a short delay while the driver changes end, after which the train will proceed from WH592 into the siding.

Trains coming out and heading south need to reverse at either signal WH258 or signal WH592. Again, there will be a short delay while the driver changes end, so factor this into your regulating decisions.

Check the timetable carefully before routing a train out from the siding, to ensure that it is routed correctly.

St. Albans Ground Frame

[In 1980s/1990s eras only]

A siding, accessible from the Down Fast via Ground Frame 974, is provided here. As the protecting signal, WH73, is a semi-automatic, release of the ground frame starts a 2 minute timer to ensure any trains approaching WH73 have a chance to stop before reversing the points. Therefore, do not attempt to operate the ground frame with a train past Radlett on the Down Fast until the rear is clear of the ground frame.

St. Albans Centre Siding

Map

The trap point protecting St. Albans Centre Siding shows as locked if a route is set over the Down Slow or Up Slow. However, it is available to move if a route is set into or out of the siding.

If the point is currently normalising, routes into or out of the siding will be temporarily unavailable for a few seconds until the movement has completed.

There is no TD berth for the siding and so a sticky note could be used to remember what is in there. There is also no track section indication so, again, a sticky note will remind you that the siding is occupied!

Harpenden

There are shunt signals on all four lines to allow trains to reverse at Harpenden. There is also a limit of shunt signal on the Up Slow.

Luton Airport Parkway

Map

This station, added more recently, was inserted between existing signals and thus no signalling changes were required. However, note that a Down train stopping at Luton Airport Parkway will appear to take a long time to get from Luton Airport Parkway to signals WH99/WH299 because of the distance from the station to the signals. Approach controlled signals will not show a proceed aspect until the train has left Luton Airport Parkway and is approaching the signal, which is detected by a separate track not indicated on the panel.

Luton

Map

The trap point between platform 2 and the North End Loop can be in the normal (throw off) position even with an overlap locked through it. The trap protects trains going towards platform 2, not an overrun from platform 2 which would run through the points and likely cause some damage.

An 8-car train can be stabled on the North End Loop by setting a route from WH463 to WH589 (when timetabled to do so). Any trains coming into platform 2 with the North End Loop occupied will have to use the warner route (yellow triangle) exit by signal WH463.

A train arriving on the Up Slow into platform 1 will lock the facing points 880A/B normal until the train is entirely within the platform. This is due to an interlocking restriction in real life.

Trains can use the north exit to Luton Up Sidings using the signals provided. However, the south end requires use of the ground frame .

There are direction arrows in platforms 1 to 3. These will drop out after a time interval, after which calling-on in the opposite direction will be possible.

Limbury Road

Map

These sidings are accessible by ground frames only. Trains entering from either direction have to reverse into the sidings, as described below, but outbound trains can leave without reversal.

Up Arrivals

Trains head from Leagrave and stop on the Up Slow before signal WH304. Ground frame 981 (Limbury Road No.1) is released by the signaller which will start a timeout. Once the timeout is expired, the ground frame operator can pull the release lever, reverse both sets of points, and operate the Down handsignal to authorise the train to reverse into the siding. The ground frame can be restored once the train is clear of the pointwork.

Down Arrivals

Trains head from Luton and stop on the Down Slow, well before Leagrave station. Ground frame 982 (Limbury Road No.2) is released by the signaller which will start a timeout. Once the timeout is expired, the ground frame operator can pull the release lever, reverse the Facing Point Lock, reverse all four point ends, and operate the Up Handsignal (Down Slow) to authorise the train to reverse into the siding. The ground frame can be restored once the train is clear of the pointwork.

Down Departures

Once the signaller has been informed that a train is ready, they can release ground frame 982 (Limbury Road No.2) and wait for the timeout. Once that has expired, the ground frame operator can pull the release lever, reverse the Facing Point Lock, reverse all four point ends, and operate the Down Handsignal (Sidings) to authorise the train to move out of the siding. The ground frame can be restored once the train is clear of the pointwork.

Up Departures

Once the signaller has been informed that a train is ready, they can release ground frame 981 (Limbury Road No.1) and wait for the timeout. Once the timeout is expired, the ground frame operator can pull the release lever, reverse both sets of points, and operate the Up Handsignal (sidings) to authorise the train to move out of the siding. The ground frame can be restored once the train is clear of the pointwork.

Line Speeds

The following gives an idea of the line speed for Panel 2. For simplicity, not all small changes are noted, just the main differences. Crossovers and sidings not mentioned are rated at 15mph.

The Fast lines generally have a speed limit of 110mph all the way from Silkstream Junction to Leagrave, with the following exceptions:

• Hendon area: 105mph
• 100mph through Elstree Tunnel
• 100mph from Napsbury to St. Albans
• 105mph from Harpenden to Chiltern Green
• 100mph-95mph-90mph Chiltern Green to Luton
• 100mph Luton North Junction

Slow lines generally have a speed limit of 90mph all the way from Hendon to Leagrave, with the following exceptions:

• 60mph Silkstream Junction area
• 75mph through Elstree Tunnel
• 65mph through St. Albans
• 85mph from Harpenden to Chiltern Green
• 70mph through Luton
• 85mph through Luton North Junction

In addition, these crossovers have the following speeds:

• 40mph Radlett Junction
• 40mph Harpenden Junction
• 20mph platform 2 at Luton
• 30mph Luton North Junction

West Hampstead Contents

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Last edited by Steamer on 20/12/2020 at 14:12