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42-608: The Mattapan Line (alternatively the Mattapan Trolley and historically the Ashmont–Mattapan High-Speed Line ) is a partially grade-separated light rail line which forms part of the MBTA's Red Line rapid transit line. The line, which runs through Boston and Milton, Massachusetts , opened on August 26, 1929, as a conversion of a former commuter rail line. It exclusively uses PCC streetcars built in

84-507: A jet engine-powered snowblower , officially the Portec RMC Hurricane Jet Snow Blower, model RP-3, dubbed "Snowzilla". Snowzilla weighs 26,000 pounds (12,000 kg), measures 8 by 12 by 27 feet, and is powered by a Westinghouse J34 turbojet engine. It uses approximately 500 US gallons (1,900 L; 420 imp gal) of jet fuel per line clearing run. Other T lines simply run regular trains to clear

126-452: A grade-separated junction may be referred to as a grade separation or as an interchange – in contrast with an intersection , at-grade , a diamond crossing or a level crossing , which are not grade-separated. Roads with grade separation generally allow traffic to move freely, with fewer interruptions, and at higher overall speeds; this is why speed limits are typically higher for grade-separated roads. In addition, reducing

168-416: A highway) that they cross. However, grade-separated pedestrian crossings with steps introduce accessibility problems. Some crossings have lifts , but these can be time-consuming to use. Grade-separated roads that permit for higher speed limits can actually reduce safety due to 'weaving' (see below) as well as a perceived sense of safety. The term is most widely applied to describe a road junction in which

210-414: A partial grade separation will accomplish more improvement than for a road), and because at-grade railway connections often take up significant space on their own. However, they require significant engineering effort, and are very expensive and time-consuming to construct. Grade-separated pedestrian and cycling routes often require modest space since they do not typically intersect with the facility (such as

252-596: Is an integral part of the modern MBTA transit system rather than a tourist attraction. A rebuild of the line for modern light rail vehicles is planned. The Dorchester and Milton Branch Railroad opened in December 1847 from Neponset on the Old Colony Railroad main line to Mattapan station in Dorchester via Milton Mills (later Milton Lower Mills, then simply Milton). The line was immediately leased by

294-419: Is fully grade-separated, i.e. traffic on one road does not have to stop at yield lines or signals on one road, but may have to do so when switching to the other: On roadways with grade-separated interchanges, weaving is a result of placing an exit ramp a short distance after an entry ramp, causing conflicts between traffic attempting to leave the roadway at the next junction and traffic attempting to enter from

336-730: Is known as a flying junction and one which is not a level junction . In 1897, the London and South Western Railway (LSWR) made use of a flying junction at Worting Junction south of Basingstoke to allow traffic on the Salisbury and Southampton routes to converge without conflicting movements; this became known as "Battledown Flyover". Also in Britain, the Southern Railway later made extensive use of flying junctions on other parts of its busy former LSWR main line. Today in Britain,

378-595: The Boston Elevated Railway (BERy) was first constructing its rapid transit Cambridge–Dorchester line in the early 1910s, plans called for the line to be extended south from Andrew to Codman Square via Edward Everett Square , Columbia Square, and Mount Bowdoin. The route would have paralleled the New Haven's Shawmut branch and Midland Division . By the end of that decade, however, passenger traffic on both New Haven-owned lines had been decimated by

420-526: The Great Central Railway , built between 1896 and 1899, was the first fully grade-separated railway of this type in the UK. This also applies to light rail and even to street cars . Attempts have been made to increase the capacity of railways by making tracks cross in a grade-separated manner, as opposed to the traditional use of flat crossings to change tracks. A grade-separated rail interchange

462-679: The Green Line ) was reported to be the most viable option. As of 2024, the MBTA plans to have Type 9 LRVs replace the PCC streetcars. The Mattapan Line fleet of PCC streetcars consist of ten units, of which 6 are in service. Of the six in service, 3 have been rebuilt. [REDACTED] Media related to Ashmont–Mattapan High Speed Line at Wikimedia Commons Other transit in the United States: Grade separation In North America,

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504-482: The 1940s. Passengers must transfer at Ashmont to access the rest of the Red Line, which uses heavy rail metro rolling stock. The trolley's 2.6-mile (4.2 km) route is used only by streetcars and has just two public grade crossings. All stations have low platforms , but all except Valley Road have been retrofitted with wheelchair lifts or wooden ramps for accessibility. Unlike most heritage streetcar lines, it

546-583: The A4/M5 junction west of Bristol . Weaving can often cause side-on collisions on very fast roads with top speeds of up to 200 kilometres per hour, as well as the problem of blind spots. Where junctions have unusual designs weaving can be a problem other than on the main road. An example of this can be found at Junction 7 of the M6, where traffic joining the roundabout from the M6 Eastbound off-slip must weave with

588-670: The BERy's network of electrified streetcar lines, which connected to rapid transit trains at Forest Hills , Egleston , Dudley Square , and Andrew . Around 1920, BERy reached an agreement with the New Haven and the Boston Transit Commission to pursue the Dorchester Circuit Plan. Under that plan, a bidirectional rapid transit loop would run south from Andrew along the Old Colony main line, take over

630-458: The Eastbound off-slip must leave. Weaving can be alleviated by using collector/distributor roads or braided ramps to separate entering and exiting traffic. In railway construction, grade separation also means the avoidance of level crossings by making any roads or footpaths crossing the line either pass under or over the railway on bridges . This greatly improves safety and is crucial to

672-566: The MassDOT board in June 2016, allocated $ 9 million to the line including $ 3.7 million for maintaining the PCC cars. The plan also allocated $ 5 million for "PCC Car Replacement-Alternative Service" which was to be used for future funding should an alternate form of transportation be decided upon. In 2017, MBTA began a $ 7.9 million project to overhaul the trolleys and update the propulsion systems, but further problems such as fluctuations in power damaged

714-570: The Old Colony as its Milton branch. The Old Colony built the Shawmut Branch Railroad from Harrison Square on the main line to Milton Lower Mills via Peabody Square in 1872. Most Mattapan passenger service switched to use the new branch east of Milton, as it ran through dense urban neighborhoods rather than swamps. The Old Colony Railroad and its branches were acquired by the New York, New Haven and Hartford Railroad in 1893. When

756-533: The Red Line designation was also applied to the line, which had been known as 28 Mattapan–Ashmont. On March 18, 1968, the Neponset River flooded the line at Milton . Restoration work began at 6:00 am on March 21 as the waters receded; service was resumed by 4:30 pm. In January 1981, the MBTA proposed to close the Mattapan Line at all times beginning that March due to severe budget issues. The closure

798-651: The Shawmut Branch and Milton branch to Mattapan, cut over to the Midland Division on a tunnel, and return to Andrew via the Midland Division right-of-way and another tunnel segment. Although the Midland Branch served more populated areas, real estate deals along the Shawmut branch stood to benefit key state politicians. Construction of a rapid transit extension to Mattapan via the Shawmut branch

840-515: The capacity of a road compared to an identical road with at-grade junctions. For instance, it is extremely uncommon to find an at-grade junction on a British motorway ; it is all but impossible on a U.S. Interstate Highway , though a few do exist. If traffic can traverse the junction from any direction without being forced to come to a halt, then the junction is described as fully grade separated or free-flowing . These junctions connect two freeways: These junctions connect two roads, but only one

882-470: The city of Boston, but most of the southern half of its route is in the northern part of the neighboring town of Milton . It follows the right-of-way of two former Old Colony Railroad branches which had commuter rail service until the 1920s. Much of the route parallels the Neponset River , crossing it twice. The right-of-way is owned by the MBTA and has only two at-grade crossings on its 2.6-mile (4.2 km) route. Between Cedar Grove and Butler stations,

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924-725: The complexity of traffic movements reduces the risk of accidents . Grade-separated road junctions are typically space-intensive, complicated, and costly, due to the need for large physical structures such as tunnels, ramps, and bridges. Their height can be obtrusive, and this, combined with the large traffic volumes that grade-separated roads attract, tend to make them unpopular to nearby landowners and residents. For these reasons, proposals for new grade-separated roads can receive significant public opposition. Rail-over-rail grade separations take up less space than road grade separations: because shoulders are not needed, there are generally fewer branches and side road connections to accommodate (because

966-571: The direct flow of traffic on one or more of the roads is not disrupted. Instead of a direct connection, traffic must use on and off ramps ( United States , Australia , New Zealand ) or slip roads ( United Kingdom , Ireland ) to access the other roads at the junction. The road which carries on through the junction can also be referred to as grade separated . Typically, large freeways , highways , motorways , or dual carriageways are chosen to be grade separated, through their entire length or for part of it. Grade separation drastically increases

1008-415: The existing PCC cars, procurement of new replicas of historic cars, and turning the line into a busway. Local politicians and citizens who live along the line have voiced their concerns over the potential conversion of the line into a busway and prefer that the route be maintained as using rail technology. In January 2019, eventual conversion for use of new light rail vehicles (or Type 9 LRVs transferred from

1050-636: The faster speed requires grade separation. Therefore, many high speed lines are elevated, especially in Taiwan and Japan , where population density alongside high speed lines is higher than in France, Italy or Germany. In the United States, a flying junction on the Nickel Plate Road through Cleveland , Ohio , United States was completed in 1913. The most frequent use was later found on

1092-508: The former Pennsylvania Railroad main lines. The lines are included as part of the Northeast Corridor and Keystone Corridor now owned by Amtrak . The most complex of these junctions, near Philadelphia Zoo , handles railway traffic for Amtrak, SEPTA , New Jersey Transit , Norfolk Southern , CSX Transportation , and Conrail . In what is known as "area 1520" , which includes the former Soviet Union and other regions using

1134-507: The four operating trains in early 2018. On February 5, 2018, it was reported that eight more trolleys were going to re-enter service in 2019, the fixes will prolong the lifespan of the trains by another 7 to 8 years. After several delays, the first rebuilt trolley entered service in March 2022. The MBTA also announced in 2018 that it was studying alternatives again to running trolleys. Alternatives that were being considered were further repairs of

1176-556: The latter rebuild, the cars were repainted from their former Green Line paint scheme to a brighter orange and cream design, similar to their original coloring. The cars also carry a unique geographic MBTA logo, reminiscent of the old Metropolitan Transit Authority map logo found on the cars between 1948 and 1955. On several occasions, the MBTA has proposed to replace the PCC streetcars either with newer trolleys or with buses, and has met with substantial community opposition on each occasion. The FY2017-FY2021 Capital Investment Plan, approved by

1218-504: The line runs through the center of the Cedar Grove Cemetery. As of July 2023, the line operates on 6 minute headways at weekday peak hours and 12–13 minute headways at other times. On March 20, 1979, three trolleys collided between Central Avenue and Valley Road stations. The first two trolleys had stopped to avoid a police car, which had become stuck on the tracks while the officer was investigating teenagers drinking near

1260-472: The line to five operable streetcars. The rolling stock consists of rebuilt PCC streetcars , which were formerly part of a fleet shared with the Green Line . The historic rolling stock is retained largely because the line, built for 1920s streetcars, would have to be substantially rebuilt to accommodate the heavier modern cars used on the Green Line. In order to clear the line of snow, the MBTA maintains

1302-405: The line's ability to operate during snowstorms, rebuild all eight stations, replace track and signals, and repair bridges. Rehabilitation of the existing fleet is happening at the same time, to extend trolley life a few more years until LRVs arrive. By 2023, work was underway on 15% design. The 2007-built loop at Ashmont station will be removed as part of the project. The line begins and ends within

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1344-546: The line. A third trolley was unable to stop in time while approaching around a blind curve; it slammed into the first two trolleys, causing injuries, but no deaths. Using funding from the American Recovery and Reinvestment Act of 2009 , the MBTA conducted a pilot test of technology similar to a collision avoidance system in an automobile, using radar and increasingly fast beeping to warn train operators of obstacles ahead. Like positive train control , it would stop

1386-544: The previous junction. This situation is most prevalent either where the junction designer has placed the on-slip to the road before the off-slip at a junction (for example, the cloverleaf interchange ), or in urban areas with many close-spaced junctions. The ring road of Coventry , England , is a notorious example, as are parts of the southern M25, the London orbital motorway , the M6/M5 junction north-west of Birmingham , and

1428-557: The safe operation of high-speed lines. The construction of new level crossings is generally not permitted, especially for high speed railway lines and level crossings are increasingly less common due to the increase of both road and rail traffic. Efforts to remove level crossings are done in the UK by Network Rail and in Melbourne as part of the Level Crossing Removal Project . The London Extension of

1470-747: The same gauge, the most complicated grade-separation railpoint is found at Liubotyn in Ukraine . Footbridges and subways (called underpasses in North America as well as in the United Kingdom when referring to roads) may be employed to allow pedestrians and cyclists to cross busy or fast streets. They are often used over and under motorways since at grade pedestrian crossings are generally not permitted. Same can be said for railways. Though introduced to Central Park in New York City in

1512-400: The tightly grouped nest of flying junctions to the north of Clapham Junction railway station —although technically a combination of many junctions—handle more than 4,000 trains per day (about one train every 15 seconds). Virtually all major railway lines no longer cross (forming an 'X' shape ) at flat level (although many diverge - i.e. 'Y' shape). On almost all high-speed railway lines,

1554-517: The tracks of snow, but the PCC cars' traction motors would short out if they were used for that purpose. The current set of PCC cars are "Wartime" PCCs, built by Pullman-Standard in 1945–46. They have been in continuous revenue service in Boston since their construction, although PCC cars were not assigned to the Mattapan Line until 1955. The current fleet was rebuilt as part of a systemwide PCC rebuild program in 1978–83, and again in 1999–2005. During

1596-548: The traffic already on the roundabout wishing to use the M6 Westbound on-slip. This is as a result of the slip roads on the west side of the junction connecting to the roundabout on the inside of the eastern arc rather than the outside of the western arc as is normal. The two slip-roads are connected by a single lane on the inside of the roundabout, which traffic wishing to use the Westbound on-slip must join, and traffic from

1638-487: The train if the driver did not take action to avoid an impending collision. If successful, the system would be considered for deployment on the Green Line , where multiple collisions had occurred in recent years. On November 26, 2014, an out-of-service streetcar collided with an in-service streetcar near Cedar Grove. Seven people were injured. On December 29, 2017, a collision between two in-service streetcars caused 17 injuries. The accident, caused by operator error, reduced

1680-662: Was approved on March 23, 1923. Steam trains were discontinued in 1927 and the line was closed for two years while it was modified for streetcars. There was a debate at that time whether or not to continue subway trains from Boston to Ashmont onwards to Mattapan, but the cost of full-scale subway service was apparently too high for the Boston Elevated Railway which then operated it. The line opened from Ashmont to Milton on August 26, 1929, and from Milton to Mattapan on December 21, 1929. Infill stations were opened at Capen Street in September 1930 and Butler on October 7, 1931. In 1966,

1722-523: Was cancelled, though the Mattapan line and the Ashmont branch were closed from June 20, 1981, to January 16, 1982, for track replacement and tunnel repairs. The line's longest shutdown took place from June 24, 2006, to December 22, 2007, with shuttle buses replacing streetcar service. A new elevated loop was built at Ashmont – part of a major reconstruction of the station – and the aging canopy at Mattapan

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1764-516: Was replaced. The intermediate stations were also rebuilt; all stations except Valley Road were made accessible. Buses again replaced service on the line from October 14–29, 2023, to allow for track work. The MBTA launched the Mattapan Line Transformation project in 2019, though it was largely inactive until 2022. The project aims to replace the PCC trolleys with light rail vehicles as the Green Line fleet turns over, restore

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