Input: Article: In the United States, 25 Hz, a once-common industrial power frequency is used on Amtrak's 25 Hz traction power system at 12 kV on the Northeast Corridor between Washington, D.C. and New York City and on the Keystone Corridor between Harrisburg, Pennsylvania and Philadelphia. SEPTA's 25 Hz traction power system uses the same 12 kV voltage on the catenary in Northeast Philadelphia. This allows for the trains to operate on both the Amtrak and SEPTA power systems. Apart from having an identical catenary voltage, the power distribution systems of Amtrak and SEPTA are very different. The Amtrak power distribution system has a 138 kV transmission network that provides power to substations which then transform the voltage to 12 kV to feed the catenary system. The SEPTA power distribution system uses a 2:1 ratio autotransformer system, with the catenary fed at 12 kV and a return feeder wire fed at 24 kV. The New York, New Haven and Hartford Railroad used an 11 kV system between New York City and New Haven, Connecticut which was converted to 12.5 kV 60 Hz in 1987.

Now answer this question: What specification is similar for both Amtrak and Septa systems?

Output: catenary voltage

Input: Article: Solar energy may be used in a water stabilisation pond to treat waste water without chemicals or electricity. A further environmental advantage is that algae grow in such ponds and consume carbon dioxide in photosynthesis, although algae may produce toxic chemicals that make the water unusable.

Now answer this question: What is a possible negative effect of algae in water stabilization ponds?

Output: toxic chemicals

Input: Article: On 2 March 1882, Roderick Maclean, a disgruntled poet apparently offended by Victoria's refusal to accept one of his poems, shot at the Queen as her carriage left Windsor railway station. Two schoolboys from Eton College struck him with their umbrellas, until he was hustled away by a policeman. Victoria was outraged when he was found not guilty by reason of insanity, but was so pleased by the many expressions of loyalty after the attack that she said it was "worth being shot at—to see how much one is loved".

Now answer this question: When did Maclean attempt to shoot Victoria?

Output:
2 March 1882