Gauntlet track

Gantlet track on the Croydon tramlink, Mitcham

Gantlet track (or gauntlet track) is where railway tracks converge onto a single roadbed and are interlaced to pass through a narrow passage such as a cutting, bridge, or tunnel. A frog at each end allows the two tracks to overlap, and the four rails run parallel through the passage on the same crossties and separate again at the other end. This technique requires only slightly more width than a single track and eliminates the complexities of a switching system since both tracks remain discrete.

Usage and origins

Gantlet tracks are commonly used when a rail line's capacity is increased with the addition of an additional track, but cost or other factors prevent the widening of the bridges. Since there are no points or other moving parts on gantlet track, a train operating on one of the tracks cannot be routed onto the other. Because two trains cannot use the gantlet at the same time, scheduling and block signals must allow for this restriction.

The term is derived not from gauntlet meaning a type of glove, but from the expression running the gauntlet, which means running between two confining rows of adversaries.

Gantlet track can also be used to move a switch away from a heavily trafficked road, as used on the Mannheim tram system.

Gantlet track is typically used for short stretches of track where it is cheaper to provide extra rails than to provide switches and reduce the line to single track.

Examples worldwide

Germany: gantlet track in Mannheim.

America

Gantlet track can also be used when railroads of different gauges share right-of-way; the standard-gauge Delaware, Lackawanna and Western Railroad used the wide-gauge Erie Railroad's tunnel through the New Jersey Palisades in this way before the DL&W built its own tunnel. The DL&W also used gantlet track to allow two sets of track of the same gauge to pass through the Oxford Tunnel in Oxford, New Jersey. In this latter arrangement, the tracks overlapped within the tunnel, without the use of switches, so that the tracks travelled down the center of the tunnel where the overhead clearance was greater. The disadvantage of such an arrangement is that the tunnel has only single-track capacity. On low-density traffic lines, such an arrangement would probably not be problematic, although higher density use could cause delays.

Gantlet track, with active switches, is used on tracks shared by both passenger and freight trains, when the tracks pass through a station with high-level platforms. The gantlet track is used to give the freight trains the clearance they need. An example is at Union Station, on the Raritan_Valley_Line in New Jersey.

Australia

The Como River bridge was built as single line in the 1880s. The line was duplicated soon after, except for the bridge. The bridge was fitted with gantlet track, which needs no turnouts, and hence needs no signal box at the far end. The bridge was replaced with a double-track bridge around 1973.

Another example is visible in the tunnel under George Street, Railway Square, as part of the spur which leads from the connection between Sydney's intercity terminus and Redfern. This was a two-track tunnel (one of the oldest on the New South Wales railways) but became gauntlet track when the line was electrified to allow electric locomotive-hauled freight trains to access the former Darling Harbour. There was insufficient clearance in the tunnel to install overhead catenary above both tracks. A single track continues on to the PowerHouse Museum and can be visited as part of the Ultimo Pedestrian Network. This track formerly served the Darling Harbour goods yards and was disconnected from the rest of the corridor which now forms part of the Sydney Light Rail network.

Canada

Gantlet track exists on the Canadian Pacific Railway Bridge across the Rivière des Prairies between Montréal and Laval because the structure gauge is not sufficiently wide for double track. This bridge is used by freight trains of the Canadian Pacific Railway (CPR), the Chemins de Fer Québec-Gatineau (CFQG) (or the Quebec Gatineau Railway (QGR)) and by the Blainville-Saint-Jerome Line suburban trains of the Agence métropolitaine de transport (Metropolitan Transportation Agency)

Germany

In Mannheim, gantlet track is used to shift the switch out of the road to prevent the switch from being driven over by cars and trucks. Mannheim also uses gantlet track to run trams within less space.

Netherlands: short section of gantlet track at a tram stop in Amsterdam

The Netherlands

Because of space constraints, Amsterdam's tram network uses gantlet track for two main routes through small streets in the city centre, and on one line gantlet tracks are used to make room for platforms at a tram stop.

Portugal

The Lisbon tram system interlaces to negotiate one particularly narrow corner in Alfama.

United Kingdom

In Britain gantlet track is usually called interlaced track and was often used where street tramways had to pass through narrow streets and even archways in ancient city walls.

• Nottingham Express Transit: just north of The Forest, to avoid a set of points in the middle of a road junction.

• Tramlink in South London: at Mitcham, where a short obstruction prevents double track being used; and at Church St, to avoid a set of points in the middle of a road junction.

• The National Tramway Museum: short section under the narrow Bowes-Lyon Bridge, which causes logistical problems on major running days.

See also

• Rail terminology (US/UK differences highlighted)

External links

• Gauntlet track - four rails in Minneapolis (with diagram)
• nycsubway.org - picture of Gantlet Track at Union Station