Question: What age was the American social entrepeneur who was one of eight who got killed in 2015 when an Amtrak train travelling from Washington, D.C. to New York City derailed?

Context articles: Merchants Limited
Atlantic City Express (Amtrak train)
2013 VIA Rail Canada terrorism plot
Everett Station
Three Rivers (train)
Falls of Cruachan derailment
Amtrak's 25 Hz traction power system
Rachel Jacobs
Garrison train crash
2015 Philadelphia train derailment

The Merchants Limited, sometimes shortened to Merchants, was a New York, New Haven and Hartford (the "New Haven") passenger train on the Shore Line between Boston and New York City.
 It was the New Haven's premier passenger train and the last all-parlor car train in the United States.
 The train entered service in 1903, and survived the turbulent Penn Central merger to become one of Amtrak's Boston–Washington, D.C. services.
 The name disappeared from Amtrak's timetables in 1995 when most Northeast trains were rebranded "NortheastDirect".
The Atlantic City Express was an Amtrak train that ran from both New York City and Washington, D.C. to Atlantic City, New Jersey, in the Northeastern United States.
 The train operated on the Northeast Corridor from New York City and Washington, D.C. to 30th Street Station in Philadelphia, Pennsylvania, where it went east to Atlantic City.
The 2013 Via Rail Canada terrorism plot was a conspiracy to commit terrorist acts in and against Canada in the form of disruption, destruction or derailment of trains operated by Canada's national passenger railway service, Via Rail Canada.
 The alleged targeted train route was the "Maple Leaf", a joint Via Rail and Amtrak train service between Toronto and New York City.
 The two suspects, Chiheb Esseghaier and Raed Jaser, were arrested on April 22, 2013 by the RCMP and subsequently charged by the Crown in connection with the plot.
 Neither one is a Canadian citizen.
Everett Station is an Amtrak train station serving the city of Everett, Washington.
 The station has provided service to the "Cascades" and "Empire Builder" routes since its opening in 2002, replacing an earlier station near the Port of Everett.
 The four-story building also houses social service programs and is the center of a 10 acre complex that includes parking lots and a large bus station used primarily by Community Transit, Everett Transit, and Sound Transit Express.
 The station has served as the northern terminus of the Sounder North Line since 2003 and Swift Bus Rapid Transit since 2009.
 It consists of two side platforms, one serving Amtrak and the other serving Sounder commuter trains.
 Everett Station also functions as a park and ride, with 1,067 short-term parking spaces located in lots around the station after it was expanded by Sound Transit in 2009.
The Three Rivers was a daily Amtrak train running between New York City and Chicago, Illinois.
 It operated via Philadelphia, Pennsylvania, Pittsburgh, Pennsylvania and Akron, Ohio.
 The "Three Rivers" replaced the "Broadway Limited" in 1995.
 The route was cancelled, with the last train running on March 7, 2005, due to Amtrak's unilateral cancellation of a United States Postal Service contract on the line.
The Falls of Cruachan derailment occurred on 6 June 2010 on the West Highland Line in Scotland, when a passenger train travelling between Glasgow and Oban hit boulders on the line and derailed near Falls of Cruachan railway station, after a landslide.
 The two-car diesel multiple unit caught fire (which was soon put out with fire extinguishers) and one carriage was left in a precarious position on the 50 ft high embankment.
 Sixty passengers were evacuated, some with minor injuries; eight of those were hospitalised as a precaution.
 However, no people were killed.
 In addition to blocking the line, the incident also caused the closure of the A85 road below the rail line.
 Both road and rail were closed for a week.
Amtrak's 25 Hz traction power system is a traction power grid operated by Amtrak along the southern portion of its Northeast Corridor (NEC): the 225 route miles (362 km) between Washington, D.C. and New York City and the 104 route miles (167 km) between Philadelphia and Harrisburg, Pennsylvania.
 The Pennsylvania Railroad constructed it between 1915 and 1938.
 Amtrak inherited the system from Penn Central, the successor to Pennsylvania Railroad, in 1976 along with the Northeast Corridor.
 This is the reason for using 25 Hz, as opposed to 60 Hz – which is the standard for power transmission in North America.
 In addition to serving the NEC, the system provides power to New Jersey Transit Rail Operations (NJT), the Southeastern Pennsylvania Transportation Authority (SEPTA) and the Maryland Area Regional Commuter Train (MARC).
 Only about half of the system's electrical capacity is used by Amtrak.
 The remainder is sold to the commuter railroads who operate their trains along the corridor.
Rachel Jacobs (October 3, 1975 – May 12, 2015) was an American social entrepreneur and CEO of a tech company.
 She was killed at age 39 in the 2015 Philadelphia train derailment while commuting between her home in New York and the Philadelphia offices of ApprenNet, the educational technology company she had recently joined as CEO.
The Garrison train crash occurred on October 24, 1897, in Garrison, New York, on a Sunday morning, at approximately 5:47 am, when train No. 46 of the New York Central & Hudson River Railroad derailed near King's Dock of the Hudson River division, about one and three-quarters miles south of Garrison.
 19 people were killed, all but one of whom drowned when the embankment gave way plunging the train into the Hudson River.
 Witnesses described feeling between one and three "thuds" before three of the five sleeper cars fell into the river.
 Several witnesses described seeing a "hole" in the trackbed after the accident, however, the cause of this was not determined.
 Early speculation blamed a large explosion of dynamite as the cause of the train's derailment.
 Two weeks previously, the same train had almost derailed near the same spot when a two-ton boulder was found on the tracks, with some believing it had been deliberately placed.
On May 12, 2015, an Amtrak "Northeast Regional" train from Washington, D.C. bound for New York City derailed and wrecked on the Northeast Corridor in the Port Richmond neighborhood of Philadelphia, Pennsylvania.
 Of 238 passengers and 5 crew on board, 8 were killed and over 200 injured, 11 critically.
 The train was traveling at 102 mph in a 50 mph zone of curved tracks when it derailed.