Simran is not a “Reet” started by Bhai Randhir Singh. This is another of them silly made up stories which Punjabis pass to the next man in the Gurdwara, without ever researching to see if it is actually true. In fact, Gursikhs who were companions of Bhai sahib state he never did simran in keertan. He only did keertan of the Gurbani Shabad. Plus he only did one shabad at a time rather than a number of shabads on a specific subject, which are common now. So when he did keertan for 48 hours at a time in Main Historical Gurdwaras, he did one shabad only, but got so deep into that one shabad than he meditated on it for 48 hours, which shows his Jeevan.
Stand alone Simran - as many now do with wajas in akhand jaaps or 1hour simran programmes is a relatively new phenomenom. In fact, I believe its real pioneer was Bhai Sahib Rama Singh. If we listen to keertan at Sri Harmandar sahib, you will never hear simran, neither are people allow to sing with the kirtanees in the jatha style. It is true that Akhand kirtani Jatha has introduced a different style of keertan to the Panth, but this was after Bhai sahib Randhir Singh. Whether it is new, or something re-introduced, which was lost over time, is open to debate? This style of keertan is called “Sangatee keertan”, in which the whole sangat sings along aswell. Is this wrong? I do not see why? Surely the essence of keertan is that everyone sings and meditates, rather than sitting silently which only makes the mind wonder or makes one fall asleep. Go to any rainsbhai and you will see plenty of sangat compared any raagi darbaar that happens every week at the Gurdwara. People travel all over the country because they get Gurbani Rass from “Sangaatee keertan”. Many Gursikhs state that meditating on Naam by oneself, has certain Rass, but in sangat you benefit from everyone, so it is like a tidal wave of Rass.
Is doing Simran wrong in Sangat? Firstly is doing Simran wrong? No, it is essential part of sikhi. All Gurbani leads us to the direction of Naam Simran. If you were to do a search of Gurbani for references to Naam, you will get the whole Sahib Siri Guru Granth Sahib. Naam is Sikhi. “Raam Naam Sabh Hai Raam Nama” is Guru ji saying everything is Naam, so how can it be avoided or wrong?